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Explored by Author: Taplin, David

TAPLIN D M R

 

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Bibliographic Information

Creep fatigue phenomena in fiber-reinforced glass-ceramic-matrix composites. Boccaccini, A. R.; West, G.; Taplin, D. M. R.; Lewis, M. H.Sch. Metallurgy and Materials,Univ. Birmingham,Birmingham,UK.Editor(s): Aldinger, F.; Mughrabi, H.Materialwiss. Grundlagen, Symp. 7, Werkstoffwoche '96(1997),Meeting Date 1996,829-834.Publisher: DGM Informationsgesellschaft,Oberursel, GermanyCODEN: 65NYAAConferencewritten in German.CAN 128:131273AN 1998:67611CAPLUS

 

Abstract

Mech. testing for detn. of creep fatigue in fiber-reinforced glass-ceramic-matrix composites [with barium magnesium aluminosilicate matrix and unidirectional Si-Ti-C-O (Tyranno) fibers], at three creep loads (of 240, 210, and 180 MPa) and 1100°, resulted in measurement of a continuously decreasing creep rate over 138 h testing.Cyclical testing with variable loads resulted in a recovery of creep elongation during cycles.Such a behavior has implications for materials that operate under cyclic conditions at high temp.

 

Bibliographic Information

Creep study of 2618Al alloy and its SiC particulate reinforced composite. Singh, R. P.; Pandey, M. C.; Taplin, D. M. R..Defence Metallurgical Res. Lab.,Hyderabad,India.Trans. Indian Inst. Met.(1996),49(4),431-435.CODEN: TIIMA3ISSN: 0019-493X.Journalwritten in English.CAN 126:254101AN 1997:240917CAPLUS

 

Abstract

Creep behavior of 2618 aluminum alloy-silicon carbide composite has been studied at 500 K in the stress range of 110-200 MPa and the results are compared with that of the monolithic alloy.The creep studies showed that reinforcement by silicon carbide particulate in the alloy did not improve the creep behavior, instead it led to a weakening effect resulting in higher creep rate and reduced creep life.Creep weakening in the composite is believed to be due to the combined effects of silicon carbide particulates and fine grain size.Nucleation of voids occurred around the SiCp leading a dimple type of fracture in the composite whereas the mode of fracture was predominantly intergranular in the monolithic material.

 

Bibliographic Information

The role of volume to surface area ratio of creep specimens on rupture life of nickel base superalloys. Pandey, M. C.; Srinivas, S.; Satyanarayana, D. V. V.; Taplin, D. M. R..Defence Metallurgical Res. Lab.,Hyderabad,India.Trans. Indian Inst. Met.(1996),49(4),425-429.CODEN: TIIMA3ISSN: 0019-493X.Journalwritten in English.CAN 126:254100AN 1997:240912CAPLUS

 

Abstract

The influence of specimen geometry and size on rupture life of nickel-based superalloys has been elucidated by analyzing the published data. The analyses of creep data obtained for different specimen geometries show that vol.-to-surface area ratio (V/S) of specimens exerts considerable influence on rupture life, particularly when V/S is low. It is further demonstrated that there exists a synergistic effect between grain size and V/S on rupture lives on nickel base superalloys.

 

Bibliographic Information

Creep behavior of a precipitation hardenable austenitic stainless steel.Satyanarayana, D. V. V.; Pandey, M. C.; Taplin, D. M. R..Defence Metallurgical Res. Lab.,Hyderabad,India.Trans. Indian Inst. Met.(1996),49(4),419-423.CODEN: TIIMA3ISSN: 0019-493X.Journalwritten in English.CAN 126:266751AN 1997:240911CAPLUS

 

Abstract

Creep behavior of a model Fe-Ni-Cr-Al alloy was studied at temps. 823, 873 and 923 K in the stress range 200-450 MPa.The stress dependence of min. creep rate at all the three temps. can be represented by a power law with stress exponent of 10.The apparent activation energy Qc for creep was about same as that for lattice self diffusion of g-iron i.e., 282 kJ/mol.The high stress exponent obsd. for the present alloy, although typical of particle-strengthened alloys, can not be explained on the basis of threshold stress because Qc is close to the activation energy for lattice self-diffusion of g-iron.The exptl. min. creep rate vs. time-to-rupture data followed the Monkman-Grant relation quite well, indicating that time-to-rupture is controlled by growth of grain boundary cavities.

 

Bibliographic Information

Densification and crystallization of glass powder compacts during constant heating rate sintering. Boccaccini, A. R.; Stumpfe, W.; Taplin, D. M. R.; Ponton, C. B.Department of Environmental Sciences,University of Plymouth,Plymouth,UK.Mater. Sci. Eng., A(1996),A219(1-2),26-31.CODEN: MSAPE3ISSN: 0921-5093.Journalwritten in English.CAN 126:78602AN 1997:40083CAPLUS

 

Abstract

Heating microscopy was used to study the interaction between the processes of densification and crystn. of glass powder compacts under const. heating rate sintering conditions without the application of external loads.For barium magnesium aluminosilicate (BMAS) glass powder compacts sintered between 800-1100 °C, it has been shown that the relative rates of crystn. and densification can be controlled by changing the heating rate.Samples sintered at a high heating rate of 15 K min-1 could be fully densified in the amorphous state, delaying the onset of crystn.In the samples sintered at a low heating rate of 1 K min-1, the onset of crystn. coincided with the termination of densification at » 1000 °C.Since the expts. were performed without an application of external loads, the results are applicable for the manufg. of dense BMAS glass-ceramics via a pressureless sintering route.

 

Bibliographic Information

The multibarriers-system as a materials science approach for industrial waste disposal and recycling: application of gradient and multilayered microstructures.Boccaccini, A.R.; Janczak, J.; Taplin, D.M.R.; Kopf, M.School of Metallurgy and Materials,The University of Birmingham,Birmingham,UK.Environ. Technol.(1996),17(11),1193-1203.CODEN: ENVTEVISSN: 0959-3330.Journalwritten in English.CAN 126:64647AN 1997:20127CAPLUS

 

Abstract

Appropriate processing techniques and tailored combinations of diverse industrial wastes, including cullet glass and residues of combustion processes, such as fly ashes from coal power stations, filter dusts from waste incinerators or slags from steel prodn., are the fundamentals of a novel waste management concept based on materials science and engineering.This approach combines melting and powder technol. processes with microstructural design to obtain recycling products with a) a biocompatible concn. of hazardous or pollutant constituents, and b) a multilayered or gradient structure effectively sepg. the remaining dangerous components from the biosphere.Thus the resulting products, being remineralized, can be either reused (e.g. as architectural or building materials) or permanently disposed of in a safe manner.This contribution is focussed on microstructural concepts for the design of layered and gradient structures in waste contg. materials.The aim is to minimize the leaching of hazardous elements, i.e. heavy metals, from the products by simultaneously improving their phys. properties and mech. behavior.Two kinds of gradient microstructures are discussed: porous sintered materials with gradient porosity and glass-ceramics with graded variation of the cryst. phase for architectural or building materials.

 

Bibliographic Information

Colloidal processing of a mullite matrix material suitable for infiltrating woven fiber preforms using electrophoretic deposition.Boccaccini, A. R.; Trusty, P. A.; Taplin, D. M. R.; Ponton, C. B.Sch. Metallurgy Mater.,Univ. Birmingham,Birmingham,UK.J. Eur. Ceram. Soc.(1996),16(12),1319-1327.CODEN: JECSERISSN: 0955-2219.Journalwritten in English.CAN 126:22018AN 1996:719248CAPLUS

 

Abstract

Com. available alumina and silica precursors for the prepn. of mullite ceramic via colloidal processing and viscous transient sintering have been identified, including fumed nanosize powders and colloidal suspensions.These materials were chosen due to the fact that they can be used in the form of a sol, as mullite matrix precursors, to infiltrate woven fiber preforms using electrophoretic deposition.The sintered d. of the mullite matrixes sintered for 2 h, at the upper temp. for fabricating SiC-fiber reinforced composites (1300°C) is only »90% of theor.However, by exploiting a viscous flow densification mechanism, it is envisaged that hot-pressing can be used to produce fully dense mullite matrix composites at the required temps.Addnl., using a simple pressureless sintering route, almost fully dense (98% of theor. d.) monolithic mullite has been obtained from the pre-mullite powders.A very homogeneous and fine microstructure was achieved by sintering for 5 h at a temp. of »1450°C.

 

Bibliographic Information

Densification and crystallization behavior of barium magnesium aluminosilicate glass powder compacts.Lambrinou, K.; van der Biest, O.; Boccaccini, A. R.; Taplin, D. M. R..Dep. Metallurgy Materials Eng.,Katholieke Univ. Leuven,Heverlee,Belg.J. Eur. Ceram. Soc.(1996),16(11),1237-1244.CODEN: JECSERISSN: 0955-2219.Journalwritten in English.CAN 125:306800AN 1996:650263CAPLUS

 

Abstract

The densification and crystn. of barium magnesium aluminosilicate (BMAS) glass powder has been investigated.The aim of the study was to draw conclusions of value for the optimization of the processing parameters for BMAS matrix ceramic composites.Pressureless sintering and hot-pressing techniques were investigated.The pressureless densification behavior of cold-uniaxially pressed compacts was detd. at isothermal and const. heating rate conditions using a high temp. microscope.The samples could be densified isothermally to full d. at 930°C prior to the onset of crystn.For compacts sintered at const. heating rates between 800 and 1100°C, it was found that the simultaneous occurrence of crystn. and densification strongly depends on the heating rate.Using hot-pressing (pressure = 20 MPa) results in full densification in the amorphous state after 1 h at 925°C.X-ray diffraction anal. was used to characterize the crystallinity of pressureless sintered and hot-pressed samples that were fabricated at temps. between 850° and 1300°C.The crystn. behavior did not change, in qual. terms, with the pressure applied during hot-pressing.Combination of the densification and crystn. results demonstrated that the BMAS glass can be densified completely at relatively low temps. (930°C) in the glassy state.The material can be subsequently crystd. at higher temps. (between 1100 and 1300°C) yielding a high-temp.-resistant microstructure consisting of Ba-osumilite, celsian and cordierite.

 

Bibliographic Information

New technologies for manufacture of fiber-reinforced ceramic composites.Boccaccini, A. R.; Trusty, P. A.; Butler, E. G.; Taplin, D. M. R.; Ponton, C. B.Sch. Metall. Mater.,Univ. Birmingham,UK.Editor(s): Ziegler, Guenter.Verbundwerkst. Werkstoffverbunde, [Vortragstexte Tag.](1996),Meeting Date 1995,57-60.Publisher: DGM Informationsgesellschaft,Oberursel, GermanyCODEN: 63LBAJConference; General Reviewwritten in German.CAN 125:254674AN 1996:591037CAPLUS

 

Abstract

In a review with 13 refs., experience with infiltration of fiber mats with a matrix material by using electrophoretic deposition and electrophoretic filtration deposition procedures is evaluated.

 

Bibliographic Information

Air-environment-creep interaction in a nickel base superalloy.Srinivas, S.; Pandey, M. C.; Taplin, D. M. R..Defence Metallurgical Research Laboratory,Hyderabad,India.Eng. Failure Anal.(1995),2(3),191-6.CODEN: EFANEMISSN: 1350-6307.Journalwritten in English.CAN 124:152863AN 1996:41095CAPLUS

 

Abstract

A Nimonic 263 alloy, widely used for combustion chamber applications in aero-engines, was exposed to air at 1020°C to study the oxidn.-creep interaction at 780°C in the stress range of 160-275 MPa.Prior exposure of the alloy led to degrdn. of creep properties, resulting in enhanced creep rate, poor rupture lifetime and creep ductility embrittlement.Degrdn. of creep properties in the air-exposed alloy has been discussed in terms of oxygen-induced damage in the grain boundary due to the formation of CO gas bubbles and the depletion of g' in the near-surface region.

 

Bibliographic Information

Creep and densification during anisotropic sintering of glass powders.Boccaccini, A. R.; Taplin, D. M. R.; Trusty, P. A.; Ponton, C. B.School of Metallurgy and Materials,University of Birmingham,Birmingham,UK.J. Mater. Sci.(1995),30(22),5652-6.CODEN: JMTSASISSN: 0022-2461.Journalwritten in English.CAN 124:35321AN 1995:957106CAPLUS

 

Abstract

The isothermal sintering behavior of a barium magnesium aluminosilicate glass powder at 930 °C was investigated using a heating microscope.The cylindrical samples exhibited a variable shrinkage anisotropy during sintering. The shrinkage anisotropy ratio, defined as the ratio of the relative change of height and diam., varied linearly between .apprx.0.3 and .apprx.0.98 with the relative vol. shrinkage during densification.Shrinkage anisotropy caused creep deformation of the samples. The creep rate varied exponentially with the densification rate and the ratio of creep to densification rates, ec/ep, decreased as densification proceeded. This is in disagreement with most previous studies, which show a const. value of ec/ep during the densification. Overall, the study points out the relevance of variable shrinkage anisotropy and how it affects the densification behavior of glass powders.

 

Bibliographic Information

Anisotropic shrinkage of barium-magnesium aluminosilicate glass powder compacts during sintering.Boccaccini, A. R.; Trusty, P. A.; Taplin, D. M. R..School of Metallurgy and Materials, The University of Birmingham,Birmingham,UK.Mater. Lett.(1995),24(4),199-205.CODEN: MLETDJISSN: 0167-577X.Journalwritten in English.CAN 123:150559AN 1995:739522CAPLUS

 

Abstract

The shrinkage behavior of barium magnesium aluminosilicate glass powder compacts has been measured at isothermal conditions using a heating microscope.The samples showed a varying shrinkage anisotropy during densification at 930°C.This behavior could not be explained solely on the basis of the pore/solid interface orientation during sintering.The exptl. values for the shrinkage behavior are in very good agreement with the theor. prediction of the stereol.-based model equation of H. E. Exner and J. Giess (1988).

 

Bibliographic Information

Creep and creep fatigue behavior of continuous fiber reinforced glass ceramic matrix composites.West, G.; Boccaccini, A. R.; Taplin, D. M. R..Dep. Environmental Sci.,Univ. Plymouth,Plymouth,UK.Materialwiss. Werkstofftech.(1995),26(7),368-73.CODEN: MATWERISSN: 0933-5137.Journalwritten in English.CAN 123:235412AN 1995:733164CAPLUS

 

Abstract

The flexural creep and creep strain recovery behavior during creep-fatigue tests of a cross-ply SiC fiber reinforced Ba Mg aluminosilicate glass-ceramic matrix composite was investigated at 1100° in air. Only heat-treated samples were tested. Stress levels of 90, 105, and 120 MPa were examd. to produce low strains. A continuously decreasing creep strain rate was obsd. with non steady-state regime. Extensive viscous strain recovery was found upon the unloading period during the short-duration cyclic creep expts. The crept composites retained their "graceful" fracture behavior after testing indicating that no damage in the matrix was induced during creep and creep-fatigue loading.

 

Bibliographic Information

Environmental ageing effects in a silicon carbide fiber-reinforced glass-ceramic matrix composite.Plucknett, K. P.; Sutherland, S.; Daniel, A. M.; Cain, R. L.; West, G.; Taplin, D. M. R.; Lewis, M. H.School Manufacturing, Materials and Mechanical Engineering, University Plymouth, Plymouth, UK.J. Microsc. (Oxford)(1995),177(3),251-63.CODEN: JMICARISSN: 0022-2720.Journalwritten in English.CAN 123:120476AN 1995:611960CAPLUS

 

Abstract

A silicon carbide fiber-reinforced glass-ceramic composite, based upon a BaO-MgO-Al2O3-SiO2 (BMAS) matrix, has been used for a study of microstructural stability (specifically interface stability) after environmental exposure at elevated temp.Characterization of the as-received material demonstrated the presence of a thin "carbon-rich" interfacial layer between fiber and matrix, as typically obsd. in glass-ceramic/silicon carbide fiber composite systems.Samples have been subjected to heat-treatments in an oxidizing atm. at temps. between 723 and 1473 K, for up to 500 h.Intermediate-temp. aging, between 873 and 1073 K, results in strong fiber/matrix bonding, with consequent degrdn. of strength and composite "ductility".This is due to oxidative removal of the carbon interfacial layer and subsequent oxidn. of the fiber surface, forming a silica bridge.Carbon is retained at higher aging temps. due to the formation of a protective surface oxide scale at exposed fiber ends.Attempts to pretreat the BMAS composite at high temp. (1273-1473 K), designed to inhibit intermediate-temp. degrdn. via the formation of silica plugs at exposed fiber ends, has given mixed results due to the high residual porosity content in these materials, allowing paths of "easy" oxygen ingress to be retained.

 

Bibliographic Information

Performance enhancement of Inconel alloy X-750 during creep via optimal solution treatment and control of morphol. of grain boundary carbide.Pandey, M. C.; Satyanarayana, D. V. V.; Taplin, D. M. R..Dep. Environ. Sci.,Univ. Plymouth,Devon,UK.Mater. Sci. Technol.(1994),10(11),936-9.CODEN: MSCTEPISSN: 0267-0836.Journalwritten in English.CAN 122:194445AN 1995:450847CAPLUS

 

Abstract

The effect of soln. treatment temp. on both the morphol. of grain boundary carbides and the creep rupture behavior of Inconel alloy X-750 has been investigated.Soln. treatment of 1050°C led to pptn. of Ti/Nb carbide along grain boundaries, and as a result the formation of chromium carbide during subsequent aging treatment was considerably affected.This led to changes in the morphol. of the grain boundary carbide and redn. in the width of 'clear' zone.This modification in the morphol. of grain boundary carbide reduced the creep resistance of the alloy, leading to a redn. in rupture lifetimes, whereas strains to fracture were unaffected.

 

Bibliographic Information

Prediction of rupture lifetime in thin sections of a nickel base superalloy.Pandey, M. C.; Taplin, D. M. R..Defence Metallurgical Res. Lab.,Hyderabad,India.Scr. Metall. Mater.(1994),31(6),719-22.CODEN: SCRMEXISSN: 0956-716X.Journalwritten in English.CAN 121:139316AN 1994:539316CAPLUS

 

Abstract

Anal. of the rupture lifetime data of a g'- strengthened nickel superalloy shows that the time-to-rupture is controlled by the vol.-surface area ratio. Furthermore, normalization of the ratio with the grain size shows that the time-to-rupture data for grain sizes of 55 and 250 mm can be represented by a single curve.

 

Bibliographic Information

Fatigue and creep of particulate reinforced aluminum based metal matrix composites at elevated temperatures.Healy, J. C.; O'Dwyer, J. G.; Taplin, D. M. R..Sch. Met. Mater.,Univ. Birmingham,Edgbaston/Birmingham,UK.Key Eng. Mater.(1992),72-74(Mater. Adv. Technol. Appl.),239-62.CODEN: KEMAEYISSN: 1013-9826.Journal; General Reviewwritten in English.CAN 117:237961AN 1992:637961CAPLUS

 

Abstract

A review with 40 refs. of the current published work in the temp. range 150-300°C, at which potential components in the automotive and aerospace industries might be expected to operate. In terms of the fatigue and creep behavior, the base alloy, size and vol. fraction of the reinforcement, crack deflection, and the strength of the interfacial bond are all important factors.

 

Bibliographic Information

Creep crack growth studies on alloy 800H tubes under complex loading conditions.Hunter, C. P.; Hurst, R. C.; Taplin, D. M. R..UNIEUX,IRSID,Firminy,Fr.Mater. High Temp.(1992),10(2),144-9.CODEN: MHTEEMJournalwritten in English.CAN 117:175771AN 1992:575771CAPLUS

 

Abstract

A novel method is described for detg. the creep crack growth (CCG) behavior of components contg. defects.Alloy 800H tubes are circumferentially notched and exposed to internal pressure, axial loading or combinations of both at 800° and the crack growth measured by using a DC potential drop method.Appropriate limit load and ref. stress calcns. enable an explanation of the stress rupture behavior.This anal. applied to the CCG results shows that the C*-integral is an appropriate parameter for describing crack growth and facilitates a demonstration of agreement between component tests and conventional (compact tension (CT) specimen) CCG approaches.

 

Bibliographic Information

Determination of the controlling multiaxial stress rupture criterion in tubular Alloy 800H components. Hunter, C. P.; Hurst, R. C.; Taplin, D. M. R..Jt. Res. Cent.,Petten,Neth.Editor(s): Bachelet, E.High Temp. Mater. Power Eng. 1990, Proc. Conf.(1990),1619-28.Publisher: Kluwer,Dordrecht, NethCODEN: 57FVAWConferencewritten in English.CAN 115:260717AN 1991:660717CAPLUS

 

Abstract

Alloy 800H tubes were tested for detg. the multiaxial stress rupture criterion.To simulate closely the plant component, precision-machined tubular specimens were subjected to multiaxial stress situations, including uniaxial tension, internal pressure, and combined loading. Each range of multiaxial stress ratio was studied at equiv. stress levels of 55 and 70 MPa in the tube wall.The tests were all taken to failure and the rupture times compared with those predicted using a continuum damage-based lifetime prediction model applied to uniaxial creep data obtained from the bar specimens. At an equiv. stress level of 70 MPa, the max. principal stress criterion is the operative multiaxial criterion, but a transition to von Mises controlled rupture at the lower stress of 55 MPa is found.Metallog. investigations of the failed tubes for the type and distribution of creep damage supports the conclusions of a transition in the controlling criterion occurring between the 2 stress levels studied. A change in the failure mode of the tubes from circumferential to axial cracking occurs at the same stress ratio at both stresses and is independent of the operative stress criterion.

 

Bibliographic Information

An analysis of specimen geometry effect on the creep life of Inconel alloy X-750.Pandey, M. C.; Taplin, D. M. R.; Ramarao, P.Def. Metall. Res. Lab.,Hyderabad,India.Mater. Sci. Eng., A(1989),A11833-9.CODEN: MSAPE3Journalwritten in English.CAN 111:238011AN 1989:638011CAPLUS

 

Abstract

The effects of section size and specimen geometry (flat, tubular, and solid specimens) on the creep behavior of a Ni superalloy were elicited. The effect of the section size was obsd. in all specimen geometries; time to fracture was progressively shortened as the specimen thickness was reduced. The creep behavior was compared on the basis of similar section size.The times to rupture of tubular specimens were considerably longer than those of flat and solid specimens while the min. creep rate at all the applied stresses was nearly unaffected by the specimen geometry. The principle of the vol. to surface ratio is applicable and the equivalence of creep life data in different geometries is obtained when a comparison is made using the ratio of the cross-sectional area to the perimeter as the normalizing parameter.

 

Bibliographic Information

The effect of prior exposure time on air-environment/creep interactions. Pandey, M. C.; Taplin, D. M. R.; Ashby, M. F.; Dyson, B. F.Def. Mater. Res. Lab.,Hyderabad,India.Acta Metall.(1986),34(11),2225-33.CODEN: AMETARISSN: 0001-6160.Journalwritten in English.CAN 105:195827AN 1986:595827CAPLUS

 

Abstract

Test pieces of Inconel X-750[11145-80-5] were exposed to a vacuum of 3 ´ 10-2 Pa at 1150° for various times before being creep tested in air at 700°.Bars of the same alloy were exposed for similar times at the same temp., but in air, before being manufd. into test pieces and tested in air at the same stress and temp. The bar-exposed material exhibited a slight improvement in creep resistance with exposure-time, which was due to grain growth. The test piece-exposed material showed a decrease in creep resistance, time-to-rupture, and ductility as the time of prior exposure increased. The cause of this environmental damage was a near-surface zone of highly cavitated grain boundaries whose depth increased with time of prior exposure such that its rate of evolution obeyed approx. parabolic kinetics.A math. model, based on the micromechanism involved, was developed that accurately predicts the exptl.-obsd. decrease in creep resistance with time of prior exposure.

 

Bibliographic Information

Environmental interaction during the high-temperature fatigue of MZC copper alloy.Tang, N. Y.; Taplin, D. M. R..Dep. Mech. Eng.,Univ. Waterloo,Waterloo,ON,Can.Editor(s): Rees, D. W. A.Environ. Probl. Mater. Durability, [Proc. Ir. Durability Fract. Conf.], 1st(1984),Meeting Date 1983,155-64.Publisher: Parsons Press,Dublin, IreCODEN: 54FRAXConferencewritten in English.CAN 103:145941AN 1985:545941CAPLUS

 

Abstract

Low-cycle fatigue tests were performed on MZC[65966-66-7] Cu alloy in both air and vacuum at 400°.The air environment marginally affected the fatigue life at 0.1 Hz, but considerably decreased the life at 0.001 Hz. Pre-exposure to air pressure of .apprx.0.01 Pa during a prior soln. treatment at 950° resulted in a severe decrease in grain-boundary strength in the surface layer. Fatigue cavitation is closely related to environmental degrdn. by oxidn. along grain boundaries.

 

Bibliographic Information

The role of environment during the hot tensile behavior of nickel-base superalloys.Pandey, M. C.; Taplin, D. M. R..Dep. Mech. Eng.,Univ. California,Davis,CA,USA.Editor(s): Rees, D. W. A.Environ. Probl. Mater. Durability, [Proc. Ir. Durability Fract. Conf.], 1st(1984),Meeting Date 1983,67-76.Publisher: Parsons Press,Dublin, IreCODEN: 54FRAXConferencewritten in English.CAN 103:145940AN 1985:545940CAPLUS

 

Abstract

The results of creep tests on Ni-19.2%Cr[12621-14-6] in air and in vacuum obtained by Shahinian and Achter (1959) were re-analyzed on the basis of recent findings for Inconel X-750[11145-80-5], and are explained in terms of the nucleation of grain boundary cavities by CO2 bubble formation.Hot tensile testing of Inconel X-750 in both air and vacuum at 2.12 ´ 10-3/h showed that the tensile strength was considerably increased, but creep ductility was enhanced significantly only at lower temps.

 

Bibliographic Information

Environmental Problems in Materials Durability.[Proceedings of the 1st Irish Durability and Fracture Conference, Trinity College, Dublin, Ireland].Rees, D. W. A.; Fitzpatrick, J. A.; Taylor, D.; Taplin, D. M. R.; Editors.Ire.(1984),326 pp.Publisher: (Parsons Press,Dublin, Ire.)Bookwritten in English.CAN 103:127680AN 1985:527680CAPLUS

 

Bibliographic Information

Micromechanisms in fatigue.Martin, J. W.; Edwards, L.Dep. Metall. Sci. Mater.,Oxford Univ.,Oxford,UK.Editor(s): Lewis, M. H.; Taplin, D. M. R.Micromech. Plast. Fract., [Rev. Pap. Symp. Honour Dr. J. W. Martin](1983),333-68.Publisher: Parsons Press,Dublin, IreCODEN: 54CVAUConference; General Reviewwritten in English.CAN 103:127429AN 1985:527429CAPLUS

 

Abstract

A review with 44 refs. on the role of microstructure in local plastic deformation assocd. with fatigue.Effect of slip distribution on cyclic stress-strain properties of metals is considered with emphasis on Al alloys.

 

Bibliographic Information

Ashby maps.Taplin, D. M. R.; Pandey, M. C.; Tang, N. Y.Trinity Coll.,Univ. Dublin,Dublin,Ire.Editor(s): Lewis, M. H.; Taplin, D. M. R.Micromech. Plast. Fract., [Rev. Pap. Symp. Honour Dr. J. W. Martin](1983),225-60.Publisher: Parsons Press,Dublin, IreCODEN: 54CVAUConference; General Reviewwritten in English.CAN 103:127428AN 1985:527428CAPLUS

 

Abstract

A review with 54 refs. on the diagrams showing the micromechanisms of creep plasticity (Ashby maps), and related deformation.Fracture and fatigue are included by the extension of such diagrams based on the normalized stress and homologous temp.

 

Bibliographic Information

The interaction of dislocations with hard particles.Humphreys, F. J.R. Sch. Mines,Imp. Coll. Sci. Technol.,London,UK.Editor(s): Lewis, M. H.; Taplin, D. M. R.Micromech. Plast. Fract., [Rev. Pap. Symp. Honour Dr. J. W. Martin](1983),1-37.Publisher: Parsons Press,Dublin, IreCODEN: 54CVAUConference; General Reviewwritten in English.CAN 103:127427AN 1985:527427CAPLUS

 

Abstract

A review with 64 refs. on dislocation interaction with particles of dispersed phases that do not deform when alloy matrix is deformed, esp. at low temps.

 

Bibliographic Information

Micromechanisms of fracture and the toughness of steel.Knott, J. F.Churchill Coll.,Univ. Cambridge,Cambridge,UK.Editor(s): Lewis, M. H.; Taplin, D. M. R.Micromech. Plast. Fract., [Rev. Pap. Symp. Honour Dr. J. W. Martin](1983),261-302.Publisher: Parsons Press,Dublin, IreCODEN: 54CVAUConference; General Reviewwritten in English.CAN 103:127063AN 1985:527063CAPLUS

 

Abstract

A review with 75 refs. on the microstructural approach to the fracture modes in steel.

 

Bibliographic Information

Stability of microstructure in precipitation hardened alloys under fatigue loading.Doherty, Roger D.Dep. Mater. Eng.,Drexel Univ.,Philadelphia,PA, USA.Editor(s): Lewis, M. H.; Taplin, D. M. R.Micromech. Plast. Fract., [Rev. Pap. Symp. Honour Dr. J. W. Martin](1983),303-31.Publisher: Parsons Press,Dublin, IreCODEN: 54CVAUConference; General Reviewwritten in English.CAN 103:108604AN 1985:508604CAPLUS

 

Abstract

A review with 55 refs., examg. the effect of cyclic strain on stability of microstructure in alloys.Shearing of ppts., planar slip, persistent slip bands, and loss of ppts. are considered in fatigue of alloys.Mechanisms of fatigue-induced ppt. damage are evaluated, including the effects of unidirectional strain.The fine-scale ppts. produced by heat treatment are not stable, but are readily destroyed by cyclic strain.

 

Bibliographic Information

Grain boundary segregation and intergranular fracture.Seah, M. P.Div. Chem. Stand.,Natl. Phys. Lab.,Teddington/Middx.,UK.Editor(s): Lewis, M. H.; Taplin, D. M. R.Micromech. Plast. Fract., [Rev. Pap. Symp. Honour Dr. J. W. Martin](1983),107-52.Publisher: Parsons Press,Dublin, IreCODEN: 54CVAUConference; General Reviewwritten in English.CAN 103:108603AN 1985:508603CAPLUS

 

Abstract

A review is given with 16 refs.Intergranular fractures showing low ductility are considered, esp. for Cr-Mo steel turbine disks as promoted by temper brittleness.

 

Bibliographic Information

Grain boundaries in high-temperature deformation.Dunlop, G. L.; Howell, P. R.Dep. Phys.,Chalmers Univ. Technol.,Goeteborg,Swed.Editor(s): Lewis, M. H.; Taplin, D. M. R.Micromech. Plast. Fract., [Rev. Pap. Symp. Honour Dr. J. W. Martin](1983),77-106.Publisher: Parsons Press,Dublin, IreCODEN: 54CVAUConference; General Reviewwritten in English.CAN 103:108602AN 1985:508602CAPLUS

 

Abstract

A review with 54 refs. includes creep, grain boundary sliding, and superplasticity of alloys.Deformation processes at high temp. are altered by grain boundaries that provide sources and sinks for vacancies. Grain-boundary sliding is an addnl. mode.The motion of grain-boundary dislocations is considered. Examples include creep of austenitic stainless steels.

 

Bibliographic Information

Superplasticity - mechanical and microstructural aspects.Arieli, A.; Mukherjee, A. K.Div. Mater. Sci. Eng.,Univ. California,Davis,CA,USA.Editor(s): Lewis, M. H.; Taplin, D. M. R.Micromech. Plast. Fract., [Rev. Pap. Symp. Honour Dr. J. W. Martin](1983),39-76.Publisher: Parsons Press, Dublin, IreCODEN: 54CVAUConference; General Review-written in English.CAN 103:108601AN 1985:508601CAPLUS

 

Abstract

A review with 98 refs. on superplasticity of alloys in high-temp. deformation.

 

Bibliographic Information

Plasticity and fracture mechanisms in ceramic alloys based on b-silicon nitride (Si3N4).Lewis, M. H.Dep. Phys.,Univ. Warwick,Coventry,UK.Editor(s): Lewis, M. H.; Taplin, D. M. R.Micromech. Plast. Fract., [Rev. Pap. Symp. Honour Dr. J. W. Martin](1983),181-224.Publisher: Parsons Press,Dublin, IreCODEN: 54CVAUConference; General Reviewwritten in English.CAN 103:91772AN 1985:491772CAPLUS

 

Abstract

A review, with 57 refs. on the micromechanisms of plasticity and fracture mechanisms in b-Si3N4-based ceramics.

 

Bibliographic Information

Fracture mechanics and brittle fracture of ceramics.Davidge, R. W.Mater. Dev. Div.,AERE,Harwell/Oxon.,UK.Editor(s): Lewis, M. H.; Taplin, D. M. R.Micromech. Plast. Fract., [Rev. Pap. Symp. Honour Dr. J. W. Martin](1983),153-79.Publisher: Parsons Press,Dublin, IreCODEN: 54CVAUConference; General Review-written in English.CAN 103:91771AN 1985:491771CAPLUS

 

Abstract

A review, with 39 refs. on fracture mechanics and brittle fracture of ceramic materials including discussions on plasticity, fracture strength, surface energy and toughness, and design engineering.

 

Bibliographic Information

Micromechanisms of Plasticity and Fracture.[Symposium Held at St. Catherine's College, Oxford, UK].Lewis, M. H.; Taplin, D. M. R.; Editors.Ire.(1983),368 pp.Publisher: (Parsons Press,Dublin, Ire.) Bookwritten in English.CAN 103:91644AN 1985:491644CAPLUS

 

Bibliographic Information

Effect of triaxial stress-state on creep fracture in Inconel alloy X-750.Pandey, M. C.; Mukherjee, A. K.; Taplin, D. M. R..Dep. Mech. Eng.,Univ. California,Davis,CA,USA.J. Mater. Sci.(1985),20(4),1201-6.CODEN: JMTSASISSN: 0022-2461.Journalwritten in English.CAN 102:224569AN 1985:224569CAPLUS

 

Abstract

Smooth specimens and circumferentially notched bars with a Bridgman notch geometry were tested uniaxially at 700° in air at 340-700 MPa.The material was notch strengthened on the basis of net section stress, sa.However, when the fracture lifetimes were plotted as a function of the Bridgman effective stress, se, all the data points fell approx. on 1 line.Cavity nucleation sites changed systematically from notch throat at the highest stress to notch root at the low stress.The notch rupture ductility in the notched specimens had a lower value than in the smooth ones at all stresses.

 

Bibliographic Information

Precipitation and aging in high-conductivity copper-chromium alloys with additions of zirconium and magnesium.Tang, N. Y.; Taplin, D. M. R.; Dunlop, G. L.Dep. Mech. Eng.,Univ. Waterloo,Waterloo,ON,Can.Mater. Sci. Technol.(1985),1(4),270-5.CODEN: MSCTEPJournalwritten in English.CAN 102:207744AN 1985:207744CAPLUS

 

Abstract

The pptn. reactions responsible for age hardening in a high-cond. Cu-Cr-Zr-Mg alloy[96033-65-7] were investigated by anal. transmission electron microscopy and compared briefly with the processes that occur in simpler Cu-Cr[96495-69-1] and Cu-Cr-Mg[85394-51-0] alloys.Aging at low temps. (400°) results in the formation of Guinier-Preston zones.Peak hardness, obtained by aging for 24 h at 450°, is a result of the fine scale pptn. of an ordered compd., possibly of the Heusler type, with the suggested compn. CrCu2(Zr, Mg).Overaging results in the formation of coarse ppts. of Cr and Cu4Zr[12159-05-6].The intergranular ppt. which forms in the Cu-Cr-Zr-Mg alloy is Cu4Zr.This phase ppts. as discrete particles on the grain boundaries and as thin (.apprx.5 nm) continuous intergranular films.

 

Bibliographic Information

Possible causes of embrittlement in 12% chromium steels used for fossil-fired power stations.Kruszynska, J. S.; Piekarski, K. R.; Taplin, D. M. R..Dep. Mech. Eng.,Univ. Waterloo,Waterloo,ON,Can.Mater. Sci. Technol.(1985),1(2),117-20.CODEN: MSCTEPJournalwritten in English.CAN 102:188778AN 1985:188778CAPLUS

 

Abstract

The effect of cooling rate on the embrittlement of a 12% Cr steel[96321-42-5] was investigated.When the cooling rate is not as fast as that produced by a liq. quench, the carbides have a tendency to segregate to the prior austenite grain boundaries. Carbide coarsening occurred after prolonged exposure at the operating temp. of 538°.The carbides pptd. at the prior grain boundaries or within the acicular martensitic structure acted as nucleation sites for microcracks. The pptn. and segregation of carbides may be promoted by applied stresses at high temps.

 

Bibliographic Information

Schema for depicting cavity nucleation during high-temperature fatigue.Tang, N. Y.; Taplin, D. M. R.; Plumtree, A.Dep. Mech. Eng.,Univ. Waterloo,Waterloo,ON,Can.Mater. Sci. Technol.(1985),1(2),145-51.CODEN: MSCTEPJournalwritten in English.CAN 102:153452AN 1985:153452CAPLUS

 

Abstract

Incubation time for nucleation of fatigue cavities at grain boundaries was introduced to explain the frequency dependence of fatigue fracture modes at elevated temps. It is suggested that for fatigue at a low frequency, the cavitation is an intrinsic response to cyclic stress, mainly occurring on grain boundaries perpendicular to the stress axis. The crit. frequency below which bulk cavitation occurs is detd. by the incubation time for cavity nucleation. Stress-concn. sites on a sliding grain boundary become nucleation sites in fatigue only at high frequencies, and are caused by the short time for stress relaxation. In both cases, environment and material chem. play an important role in stabilizing the cavity embryos. Fatigue cavity nucleation model was constructed to depict the dominant mechanisms in different stress-frequency domains.

 

Bibliographic Information

Tensile behavior of Inconel alloy X-750 in air and vacuum at elevated temperatures. Pandey, M. C.; Taplin, D. M. R.; Mukherjee, A. K.Dep. Mech. Eng.,Univ. California,Davis,CA,USA.Metall. Trans. A(1984),15A(9),1763-7.CODEN: MTTABNISSN: 0360-2133.Journalwritten in English.CAN 101:175951AN 1984:575951CAPLUS

 

Abstract

Hot tensile testing of Inconel X-750[11145-80-5] at 700° in air and vacuum at different strain rates, at 1 ´ 10-7-1.2 ´ 10-6/s, showed that testing in air had a weakening effect on properties.Creep ductility in vacuum (pO2 = 2.7 ´ 10-5 Pa) did not change appreciably with strain rate, but ductility varied when tested in air.The ductility min. occurred at 625° in air whereas considerable improvements in the creep ductilities were obsd. at 575° and 625° in vacuum.The results indicated that the environmental interaction during testing enhanced the rate of cavitation damage causing premature failure in the material.

 

Bibliographic Information

Prior deformation effects on creep and fracture in Inconel alloy X-750.Pandey, M. C.; Mukherjee, A. K.; Taplin, D. M. R..Dep. Mech. Eng.,Univ. California,Davis,CA,USA.Metall. Trans. A(1984),15A(7),1437-41.CODEN: MTTABNISSN: 0360-2133.Journalwritten in English.CAN 101:77368AN 1984:477368CAPLUS

 

Abstract

Creep fracture process in Inconel X-750[11145-80-5] is modified by room-temp. prestraining.It was obsd. that fracture in the prestrained specimens occurred due to growth and interlinkage of the prenucleated voids, whereas failure occurred by plastic instability in the non-prestrained specimens.Creep ductility and the times-to-rupture decreased progressively with room-temp. prestraining, but there is no marked influence on the min. creep rate.This is explained in terms of 2 competing processes: a weakening effect caused by prenucleation of grain boundary voids, and a hardening effect due to generation of dislocations due to the prestraining.

 

Bibliographic Information

High-temperature creep and fatigue of copper-chromium alloys.Tang, N. Y.; Taplin, D. M. R.; Dunlop, G. L.Dep. Mech. Eng.,Univ. Waterloo,Waterloo,ON,Can.Editor(s): Gifkins, R. C.Strength Met. Alloys, Proc. Int. Conf., 6th(1983),Meeting Date 1982,2665-70.Publisher: Pergamon,Oxford, UKCODEN: 49GEANConferencewritten in English.CAN 98:165456AN 1983:165456CAPLUS

 

Abstract

The high temp. creep and fatigue of high cond. Cu-Cr alloys with and without Mg and Zr addns. were related to their detailed microstructure.Improved properties were obtained with the Mg and Zr addns.This is largely due to the influence of Zr on the intergranular microstructure.

 

Bibliographic Information

Analysis of carbides formed during accelerated aging of 2.25Cr-1Mo steel.Abdel-Latif, A. M.; Corbett, J. M.; Taplin, D. M. R..Dep. Mech. Aerosp. Eng.,Univ. Delaware,Newark,DE,USA.Met. Sci.(1982),16(2),90-6. CODEN: METSC7ISSN: 0306-3453.Journalwritten in English.CAN 98:38492AN 1983:38492CAPLUS

 

Abstract

Creep properties are controlled by microstructure and the microstructure changes during creep service.Accelerated aging was used to obtain a series of simulated microstructures similar to those obsd. in specimens from 2.25Cr-1Mo steel[39362-68-0] after long-time service.The accelerated thermal aging can produce simulated service microstructures and it is possible to distinguish between the cubic carbide M6C and M23C6.Thus a comprehensive study of carbide formation and compn. could be achieved.

 

Bibliographic Information

Indentation plasticity and fracture of silicon nitride ceramic alloys.Lewis, M. H.; Fung, R.; Taplin, D. M. R..Dep. Phys.,Univ. Warwick,Coventry,UK.J. Mater. Sci.(1981),16(12),3437-46.CODEN: JMTSASISSN: 0022-2461.Journalwritten in English.CAN 96:186049AN 1982:186049CAPLUS

 

Abstract

The response of a series of 1- and 2-phase b'-Sialon surfaces to sharp diamond microindentation was examd. by optical and electron microscopy. The microhardness (H), which obeys the load-independent relation H = aP/a2 (where P and a are load and indent size, resp.) is nearly const. within the solid soln. series, indicating a retention of high covalency at large (Al and O) substitution levels. Indentation results from severe localized plasticity which is characterized by the operation of the dominant dislocation Burgers vector a[0001] in the hexagonal b lattice. The severe anisotropy in plasticity induces grain-boundary microcracking which is believed to nucleate median cracks which propagate away from the plastic zone on symmetry planes beneath the indenter. The relation between load, median crack size (c), and fracture toughness (Kc) is of the form, Kc = const. (P/c3/2) predicted theor. Values of Kc rank correctly with those from notched-beam measurements, but there is uncertainty about the value of the const.

 

Bibliographic Information

Effects of microstructural degradation on creep life prediction of 2 1/4 chromium - 1 molybdenum steel.Abdel-Latif, A. M.; Corbett, J. M.; Sidey, D.; Taplin, D. M. R..Univ. Waterloo,Waterloo,ON,Can.Editor(s): Francois, D.Adv. Fract. Res., Proc. Int. Conf., 5th(1982),Meeting Date 1981,41613-20.Publisher: Pergamon, Oxford, EnglCODEN: 47GBAYConferencewritten in English.CAN 96:185312AN 1982:185312CAPLUS

 

Abstract

Accelerated aging at 630° was performed on 2-1/4 Cr - 1 Mo steel[39362-68-0] to simulate microstructures obsd. in boiler tubing after long-time service. Results of microscopy, creep tests, and tensile tests on the simulated microstructures are reported.

 

Bibliographic Information

Grain boundaries in high-temperature fracture. Taplin, D. M. R.; Dunlop, G. L.Dep. Mech. Eng.,Univ. Waterloo,Waterloo,ON,Can.Met. Forum(1981),4(1-2),69-74.CODEN: MEFODSISSN: 0160-7952.Journal; General Reviewwritten in English.CAN 96:166852AN 1982:166852CAPLUS

 

Abstract

A review with 48 refs.

 

Bibliographic Information

The growth and linkage of holes during hot tensile deformation of two strain-rate sensitive aluminum alloys. Tait, R. A.; Taplin, D. M. R..Cullen Coll. Eng.,Univ. Houston,Houston,TX,USA.Editor(s): Miller, Keith John; Smith, Richard F.Mech. Behav. Mater., Proc. Int. Conf., 3rd(1980),Meeting Date 1979,2663-74.Publisher: Pergamon,Oxford, EnglCODEN: 44GDAJConference written in English.CAN 94:34984AN 1981:34984CAPLUS

 

Abstract

The growth of a through-thickness cylindrical hole during superplastic deformation of AA 5083[12616-86-3] and Supral 100[61089-43-8] Al alloy sheet was described by an equation.A modified form of void growth treatment due to F. A. McClintock (1968) was derived.The predicted degree of void enlargement at a given strain was about half that of the obsd. value.The overestn. in ductility arises because of the underestn. of growth rates for single voids and neglect of any addnl. growth which arises because of interaction effects between growing voids in an array.The major effect of increasing the strain rate sensitivity was to increase the void coalescence ratio.

 

Bibliographic Information

Damage mechanisms in the high temperature low cycle fatigue of a copper-chromium-magnesium alloy. Sidey, D.; Collins, A. L. W.; Taplin, D. M. R..Cent. Therm. Serv.,Ontario Hydro,Toronto,ON,Can.Editor(s): Miller, Keith John; Smith, Richard F.Mech. Behav. Mater., Proc. Int. Conf., 3rd(1980),Meeting Date 1979,2141-50.Publisher: Pergamon, Oxford, EnglCODEN: 44GDAJConferencewritten in English.CAN 94:34979AN 1981:34979CAPLUS

 

Abstract

Low-cycle fatigue tests an pptn.-hardened Cu-0.95 Cr-0.1% Mg[76130-83-1] at 673 K and const. strain range and cycle period showed that the no. of cycles to failure was dependent on wave shape.The shortest lines were assocd. with cycles contg. tensile holds and with stlow-fast unbalanced loop cycles.Metallog. indicated that the failure mechanism was wave-shape dependent.Fatigue maps are given for the Cu alloy and 304 stainless steel which display the controlling failure mechanism in terms of the lowest strain rate in the cycle and ratio of tensile to compressive strain rates.The maps are useful in detg. the limits of extrapolation technique based on a single failure mechanism.

 

Bibliographic Information

Rupture of strain-rate sensitive alloys. Langdon, T. G.; Taplin, D. M. R..Dep. Mater. Sci.,Univ. South. California,Los Angeles, CA, USA.SM Arch.(1977),2(3),329-68.CODEN: SMARDWISSN: 0376-7426.Journal; General Review-written in English.CAN 93:224164AN 1980:624164CAPLUS

 

Abstract

A review with 65 refs. on flow instability and rupture in strain-rate sensitive alloys that typically show high ductility.

 

Bibliographic Information

Fracture mechanism maps for metals, alloys and ceramics. Ashby, M. F.; Gandhi, C.; Taplin, D. M. R..Eng. Dep.,Univ. Cambridge,Cambridge,Engl.Univ. Cambridge, Dep. Eng., [Rep.] CUED/C/MATS(1979),(CUED/C/MATS/TR.55),37 pp.CODEN: UCDCDMISSN: 0309-6505.Report; General Review-written in English.CAN 92:45717AN 1980:45717CAPLUS

 

Abstract

A review is given with 384 refs.

 

Bibliographic Information

Fatigue maps and wave-shape effects on fatigue.Collins, A. L. W.; Sidey, D.; Taplin, D. M. R..Dep. Mech. Eng.,Univ. Waterloo,Waterloo,ON,Can.Can. Metall. Q.(1979),18(2),231-8.CODEN: CAMQAUISSN: 0008-4433.Journalwritten in English.CAN 92:45485AN 1980:45485CAPLUS

 

Abstract

The effect of wave shape on the failure mechanism in low-cycle high-temp fatigue failure was studied by using fatigue maps of some pptn.-hardened alloy samples.Unbalanced loop tests on A286[12671-82-8] Fe alloy, 304 stainless steel[11109-50-5], OFHC Cu, and a high-temp. Cu alloy[11101-24-9] showed that slow-fast cycling was the most damaging effect and produced the shortest fatigue lives.

 

Bibliographic Information

Flow and failure of superplastic materials.Taplin, D. M. R.; Dunlop, G. L.; Langdon, T. G.Dep. Mech. Eng.,Univ. Waterloo,Waterloo,ON,Can.Annu. Rev. Mater. Sci.(1979),9151-89.CODEN: ARMSCXISSN: 0084-6600.Journal; General Reviewwritten in English.CAN 92:26653AN 1980:26653CAPLUS

 

Abstract

A review with 116 refs. is given on the mech. aspects of superplastic deformation of alloys, and development of a plastic instability during flow in assocn. with necking.

 

Bibliographic Information

Residual creep life in low alloy ferritic steels.Sidey, D.; Abdel-Latif, A. M.; Westwood, H. J.; Taplin, D. M. R..Univ. Waterloo,Waterloo,ON,Can.Can. Metall. Q.(1979),18(1),49-56.CODEN: CAMQAUISSN: 0008-4433.Journalwritten in English.CAN 91:214870AN 1979:614870CAPLUS

 

Abstract

Predicting the residual creep life of low-alloy steel components in elec. power plants is discussed. Parametric methods of predicting long-time creep life are considered, and the reasons for their inadequacy are explained. The steel microstructure changes continuously during the service lifetime at high temps.

 

Bibliographic Information

Overview No. 3.Fracture-mechanism maps and their construction for f.c.c. metals and alloys.Ashby, M. F.; Gandhi, C.; Taplin, D. M. R..Eng. Dep.,Univ. Cambridge, Cambridge, Engl.Acta Metall.(1979),27(5),699-729.CODEN: AMETARISSN: 0001-6160.Journalwritten in English.CAN 91:95403AN 1979:495403CAPLUS

 

Abstract

Fracture-mechanism maps are diagrams with tensile stress as one axis and temp. as the other.Fields of dominance of a given micromechanism of fracture are shown.Superimposed on the fields are contours of const. time-to-fracture and the maps are constructed empirically by assembling observations and data for the fracture, or theor. via models for the individual fracture mechanisms.The first approach is developed.Maps are presented for Ni, Ag, Cu, Al, Pb and their alloys.The maps give an overview of the fracture micromechanisms and help identify the one most likely to be dominant. The maps give guidance in alloy selections for high-temp. use and extrapolation of creep-rupture data.

 

Bibliographic Information

Emerging frontiers in high temperature fracture.Taplin, D. M. R.; Sidey, D.; Gandhi, C.Dep. Mech. Eng.,Univ. Waterloo,Waterloo,Ont.,Can.Trans. Indian Inst. Met.(1978),31(3),163-8.CODEN: TIIMA3ISSN: 0019-493X.Journal; General Reviewwritten in English.CAN 90:208292AN 1979:208292CAPLUS

 

Abstract

High-temp. intergranular fracture of alloys under static and cyclic loads is reviewed with 34 refs.Development of fracture mechanism maps and fatigue fracture maps is discussed.

 

Bibliographic Information

Interaction effects during the growth of holes in a superplastically deforming medium.Tait, R. A.; Taplin, D. M. R..Dep. Mech. Eng.,Univ. Waterloo,Waterloo,Ont.,Can.Scr. Metall.(1979),13(1),77-82.CODEN: SCRMBUISSN: 0036-9748.Journalwritten in English.CAN 90:125977AN 1979:125977CAPLUS

 

Abstract

Com. AA 5083[12616-86-3] Al-Mg alloy sheet specimens with predrilled holes were strained in tension at 775 K and 6 ´ 10-5/s near max. ductility in superplastic deformation.Tensile growth rates for 2-hole arrays were increased over 1-hole controls by flow localization in ligament region at a hole major axis/spacing ratio >0.5, giving hole coalescence at 1.42.The cavity length at coalescence in cavitation tests was in agreement with the size estd. from hole tests.

 

Bibliographic Information

Grain-boundary sliding and intergranular cavitation during superplastic deformation of a/b brass.Chandra, T.; Jonas, J. J.; Taplin, D. M. R..Dep. Metall.,Univ. Wollongong,Wollongong,Aust.J. Mater. Sci.(1978),13(11),2380-4.CODEN: JMTSASISSN: 0022-2461.Journalwritten in English.CAN 90:27698AN 1979:27698CAPLUS

 

Abstract

Intergranular and interphase cavitation in binary a/b-brass was investigated in tension at 600° under conditions of superplastic deformation.The sites for nucleation of cavities were studied by quant. metallog., and the cavities were obsd. to nucleate preferentially at a-b interfaces.The process of cavitation was assocd. with grain boundary sliding, and cavity nucleation occurred at points of stress concns. at the sliding interfaces. Measurements of grain and phase boundary sliding at various interfaces showed that sliding occurred at a-b boundaries more readily than at a-a and b-b interfaces. The predominance of a-b interface cavitation was a result of greater sliding at the a-b boundary and unbalanced accommodation of sliding adjacent to this type of boundary.

 

Bibliographic Information

An experimental fracture map for uranium.Collins, A. L. W.; Taplin, D. M. R..Dep. Mech. Eng.,Univ. Waterloo,Waterloo,Ont.,Can.J. Mater. Sci.(1978),13(10),2249-56.CODEN: JMTSASISSN: 0022-2461.Journalwritten in English.CAN 90:27672AN 1979:27672CAPLUS

 

Abstract

A 2-dimensional (Ashby) fracture mechanism map with normalized stress vs. homologous temp. was constructed for metallic U from published exptl. data.U exhibits many modes of fracture so that the map is of particular interest.The map also has general relevance for non-cubic polycryst. materials.

 

Bibliographic Information

Fracture during fatigue and creep at high temperatures.Taplin, D. M. R.; Collins, A. L. W.; Gandhi, C.; Ashby, M. F.Dep. Mech. Eng.,Univ. Waterloo,Waterloo,Ont.,Can.Editor(s): Sih, G. C.; Chow, C. L.Proc. Int. Conf. Fract. Mech. Technol.(1977),1127-44.Publisher: Sijthoff and Noordhoff Int. Publ.,Alphen aan den Rijn, NethCODEN: 39NUARConference; General Reviewwritten in English.CAN 90:27363AN 1979:27363CAPLUS

 

Abstract

In a review with 27 refs., time-dependent, high-temp. fracture behavior of metals and alloys during fatigue and creep is discussed.A connection between fracture under a fluctuating stress and const. stress is considered. Development and use of deformation and fracture maps for prediction of service behavior are discussed.

 

Bibliographic Information

Creep fracture and residual life prediction of a petrochemical furnace tube steel. Dunlop, G. L.; Twigg, R. J.; Taplin, D. M. R..Chalmers Univ. Technol.,Goeteborg,Swed.Scand. J. Metall.(1978),7(4),152-60.CODEN: SJMLAGISSN: 0371-0459.Journalwritten in English.CAN 90:27082AN 1979:27082CAPLUS

 

Abstract

The creep cavitation and fracture at 670-875° and 30-80 MPa was detd. for centrifugally cast HK 40[12605-30-0] steel, including a melt from tubes previously given 50,000 h high-temp. service in a petrochem. furnace.The post-service cast steel showed higher secondary creep rates and shorter rupture time than did regular steel.Tests on d. of post-creep specimens were consistent with the growth of cavities by cavity condensation, but angular distribution of cavitated boundaries did not agree with this model. Fracture could be predicted from measurements of av. crack lengths, but not from crit. crack size.

 

Bibliographic Information

Fracture at high temperatures under cyclic loading. Taplin, D. M. R.; Collins, A. L. W.Dep. Mech. Eng.,Univ. Waterloo,Waterloo,Ont.,Can.Annu. Rev. Mater. Sci.(1978),8235-68.CODEN: ARMSCXISSN: 0084-6600.Journal; General Reviewwritten in English.CAN 89:184162AN 1978:584162CAPLUS

 

Abstract

A review with 106 refs.

 

Bibliographic Information

Fracture-mechanism maps for nickel, silver, aluminum and lead and certain of their alloys.Gandhi, C.; Ashby, M. F.; Taplin, D. M. R..Eng. Dep.,Cambridge Univ.,Cambridge,Engl.Univ. Cambridge, Dep. Eng., [Rep.] CUED/C-Mat(1978),(CUED/C/MATS/TR.49),44 pp.CODEN: UCDCDMISSN: 0309-6505.Reportwritten in English.CAN 89:116169AN 1978:516169CAPLUS

 

Abstract

The fracture mechanism maps were constructed for Ni, Nichrome[12605-70-8], Monel 400[11105-19-4], Ni-2 vol.%THO2[12613-58-0], Nimonic 80A[11068-71-6], Inconel X-750[11145-80-5], Ag, Al, Al alloys 2S[39323-99-4] and RR-58[12793-49-6], Pb, and Pb alloy[67296-46-2] contg. 0.7-1.0% Sb.Certain generalizations about fracture behavior were derived.

 

Bibliographic Information

High temperature creep-fatigue fracture in copper-chromium alloys. Collins, A. L. W.; Taplin, D. M. R..Dep. Mech. Eng.,Univ. Waterloo,Waterloo,Ont.,Can.Editor(s): Taplin, David M. R.Adv. Res. Strength Fract. Mater., Int. Conf. Fract., 4th(1978),Meeting Date 1977,2B839-47.Publisher: Pergamon, Elmsford, N. YCODEN: 37XRAKConferencewritten in English.CAN 89:116146AN 1978:516146CAPLUS

 

Abstract

The ductility of CuCr[59093-48-0] decreased sharply with decreasing strain and increasing temp. £673 K.The ductility of CuCrZrMg[65966-66-7] was virtually const., fracture was transgranular, and the fatigue life at 673 K and 1.7 mHz was smaller than that at 300 K.The results were rationalized in terms of fracture processes.

 

Bibliographic Information

Low cycle fatigue behavior of a superplastic aluminum bronze.Gandhi, C.; Rao, P. Rama; Taplin, D. M. R..Dep. Mech. Eng.,Univ. Waterloo,Waterloo,Ont.,Can.Met. Sci.(1978),12(1),30-4.CODEN: METSC7ISSN: 0306-3453. Journalwritten in English.CAN 89:116093AN 1978:516093CAPLUS

 

Abstract

Low cycle fatigue behavior of a superplastic aluminum bronze (9.5 wt.-% Al and 4.0 wt.-% Fe) was investigated from ambient to 1073 K.The results fit the Coffin-Manson law, DepNfb = C, where Dep is the plastic strain range, Nf the no. of cycles to failure, and b and C are consts.There were, however, certain deviations from the usual behavior of non-superplastic metallic materials.These deviations may be summarized as: (1) an increase in fatigue life with increase in temp. above .apprx.773 K; (2) a decrease in the magnitude of the exponent b to values <0.5 with increase in temp. above .apprx.773 K; (3) a square-shaped mech. hysteresis loop at 1073 K, the temp. of optimum superplastic deformation; and (4) specimen shape instability at 1073 K.These features were explained in terms of the rapidly increasing sensitivity of the flow stress to strain rate and the rapidly decreasing flow stress as the temp. is raised.

 

Bibliographic Information

The development of a fracture mechanism map for pure nickel tested in simple tension. Gandhi, C.; Ashby, M. F.; Taplin, D. M. R..Eng. Dep.,Cambridge Univ.,Cambridge,Engl.Univ. Cambridge, Dep. Eng., [Rep.] CUED/C-Mat(1977),(CUED/C/MATS/TR. 35),31 pp.CODEN: UCDCDMISSN: 0309-6505.Reportwritten in English.CAN 89:63534AN 1978:463534CAPLUS

 

Abstract

The fracture mechanisms of com. purity Ni round tensile specimens were studied, and combined with published data to give a detailed fracture mechanism map.

 

Bibliographic Information

Fracture during superplastic flow of industrial aluminum-magnesium alloys.Taplin, D. M. R.; Smith, R. F.Dep. Mech. Eng.,Univ. Waterloo,Waterloo,Ont.,Can.Editor(s): Taplin, David M. R.Adv. Res. Strength Fract. Mater., Int. Conf. Fract., 4th(1978),Meeting Date 1977,2A541-51.Publisher: Pergamon,Elmsford, N. YCODEN: 37XRAKConferencewritten in English.CAN 89:47609AN 1978:447609CAPLUS

 

Abstract

Superplastic flow and cavitation were detd. for several Al-Mg alloys after cold rolling and recrystn. 30 min at 773 K to give a 8-12m grain size.Max. elongations of 376-462% were achieved at 573-843 K.The alloys failed by growth and interlinking of cavities.No external cracks were formed.

 

Bibliographic Information

An experimental fracture-mechanism map for thoria dispersion-strengthened nickel.Gandhi, C.; Taplin, D. M. R.; Ashby, M. F.Dep. Mech. Eng.,Univ. Waterloo,Waterloo,Ont.,Can.Editor(s): Taplin, David M. R.Adv. Res. Strength Fract. Mater., Int. Conf. Fract., 4th(1978),Meeting Date 1977,2A603-11.Publisher: Pergamon,Elmsford, N. YCODEN: 37XRAKConferencewritten in English.CAN 89:29183AN 1978:429183CAPLUS

 

Abstract

Creep tests and fractog. were carried out on DS-Ni[37322-05-7] to identify fracture mechanisms.Creep curve and time-to-fracture were detd. at 583-873 K.

 

Bibliographic Information

The prediction of creep fracture in engineering alloys. McLean, D.; Dyson, B. F.; Taplin, D. M. R..Natl. Phys. Lab.,Teddington/Middlesex,Engl.Editor(s): Taplin, David M. R.Adv. Res. Strength Fract. Mater., Int. Conf. Fract., 4th(1978),Meeting Date 1977,1325-62.Publisher: Pergamon, Elmsford, N. YCODEN: 37XRAKConference; General Reviewwritten in English.CAN 89:10200AN 1978:410200CAPLUS

 

Abstract

A review with 57 refs. is given on (1) predicting the creep life under multiaxial tensile stress, (2) Kachanov damage accumulation theory, (3) physics of internal damage.

Bibliographic Information

Elevated temperature high strain fatigue of high conductivity copper alloys. Collins, A. L. W.; Taplin, D. M. R.; Singh, V. Univ. Waterloo,Waterloo,Ont.,Can.Proc. Int. Conf. Mech. Behav. Mater., 2nd(1976),871-5.Publisher: ASM,Metals Park, OhioCODEN: 36SDAEConferencewritten in English.CAN 88:125009AN 1978:125009CAPLUS

 

Abstract

In CDA 182[63142-19-8] and CDA 182 modified with Mg and/or Zr, a continuum fracture mechanics approach to fatigue crack propagation was valid in spite of void formation. The exponent in the Coffin-Manson relation did not change with frequency 170-1.7 mHz, temp. 25-400°, and £10,000 cycles. The addn. of 0.1% Mg alone was ineffective in decreasing intergranular cracking at 400°.Decrease in ductility was related to increasing size and no. of intergranular cracks.

 

Bibliographic Information

Time-dependent fatigue of an industrial copper-base alloy.Collins, A. L. W.; Singh, V.; Plumtree, A.; Taplin, D. M. R..Dep. Mech. Eng.,Univ. Waterloo,Waterloo,Ont.,Can.Met. Technol. (London)(1977),4(10),469-74.CODEN: MTNYAUJournalwritten in English.CAN 88:93528AN 1978:93528CAPLUS

 

Abstract

The high-strain fatigue behavior of CDA 175[39366-88-6] Cu alloy was studied at 25-400° in push-pull extension-controlled cycling.The alloy was examd. in 2 microstructural conditions involving variations in ppt. distributions.The time to failure and fracture characteristics were correlated with structural changes.

 

Bibliographic Information

The prediction of creep fracture from intergranular damage measurements in a copper alloy. Fleck, R. G.; Beevers, C. J.; Taplin, D. M. R..Chalk River Nucl. Lab.,At. Energy Canada Ltd.,Chalk River,Ont.,Can.Met. Sci.(1976),10(12),413-17.CODEN: METSC7Journalwritten in English.CAN 88:77612AN 1978:77612CAPLUS

 

Abstract

Cu-2.8Al-1.8Si-0.4%Co[55193-01-6] contg. grain-boundary ppts. was investigated at 923 K under const. load conditions in a vacuum of 0.67 Pa.Three types of creep test were conducted: (1) specimens were held at stresses of 9-20 MPa for 15 h (2) tests at 11 and 15 MPa were conducted for various times up to fracture (3) specimens were pulled to fracture at 11-39 MPa.Grain-boundary damage occurred by the formation and interlinkage of grain-boundary cavities.The latter occurred by a grain-boundary tearing process.Quant. metallog. revealed that the cavitation damage increased with increasing stress and time.An approach to predict the time to rupture was developed and discussed in terms of an empirical creep-rupture parameter.

 

Bibliographic Information

High-temperature fatigue cavitation in a copper alloy. Collins, A. L. W.; Cocks, G. J.; Taplin, D. M. R..Dep. Mech. Eng.,Univ. Waterloo,Waterloo,Ont.,Can.Met. Sci.(1977),11(3),87-90.CODEN: METSC7Journalwritten in English.CAN 88:77600AN 1978:77600CAPLUS

 

Abstract

The process of intergranular fatigue cavitation at 500° in a Cu alloy CDA 638[12773-57-8] was studied in low-frequency tension/compression cycling. The focus was upon the role of grain size 16-330m av. diam. Specimens were also cut transverse and parallel to the rolling direction to investigate the influence of anisotropy. Fatigue life was detd. by a damage parameter based upon crack length at coarse grain sizes (50-330m) and upon void linkage at fine grain sizes (16-50m).The idea that failure is largely controlled by the ease of final crack propagation is emphasized by the anisotropy. Material cut transverse to the rolling direction exhibited a markedly reduced life owing to the coplanarity of boundaries in the rolling direction which facilitated linkage.

 

Bibliographic Information

Fracture-mechanism maps for nickel, aluminum and lead, and certain of their alloys. Gandhi, C.; Ashby, M. F.; Taplin, D. M. R..Eng. Dep., Univ. Cambridge,Cambridge,Engl.Univ. Cambridge, Dep. Eng., [Rep.] CUED/C-Mat(1977),(CUED/C/MATS/TR.33),42 pp.CODEN: UCDCDMReportwritten in English.CAN 88:10726AN 1978:10726CAPLUS

 

Abstract

The fracture mechanisms of round tensile specimens of fcc. metals and alloys were studied. Fracture mechanism maps were constructed for Ni, Ni alloys Nichrome[12605-70-8], Monel-400[11105-19-4], Ni-2% ThO2[12605-27-5], Nimonic-80A[11068-71-6], and Inconel X-750[11145-80-5], Al, Al alloys 2S[39323-99-4] and RR-58[12793-49-6], and Pb.The maps showed 4 principal fields, corresponding to ductile fracture, transgranular creep fracture, intergranular creep fracture, and rupture. Effect of alloying on extent and position of the fields was discussed.A stable dispersion suppressed dynamic recrystn. and inhibited rupture.

 

Bibliographic Information

Combined creep-fatigue behavior of Inconel Alloy X-750.Venkiteswaran, P. K.; Ferguson, D. C.; Taplin, D. M. R..Dep. Mech. Eng.,Univ. Waterloo,Waterloo,Ont.,Can.ASTM Spec. Tech. Publ.(1973),520(Fatigue at Elevated Temp., Symp., 1972),462-72.CODEN: ASTTA8Journalwritten in English.CAN 87:155764AN 1977:555764CAPLUS

 

Abstract

The effect of superimposing a small lateral vibratory stress on the axial creep of Inconel X-750 Ni alloy at 700° was studied.Specimens simulated gas turbine blades.The fracture mode in combined creep-fatigue was a mixt. of intergranular, fatigue, and cleavage.The cleavage fracture was bowed out or serrated.The intergranular g'-ppts. arrested the propagation of cracks.This and the change in fracture mode were responsible for the lower creep rates and longer rupture lives.There was no evidence of grain boundary migration and grain size changes.

 

Bibliographic Information

Creep damage accumulation.Dyson, B. F.; Taplin, D. M. R..Div. Mater. Appl.,Natl. Phys. Lab.,Teddington,Engl.Grain Boundaries, Spring Resid. Conf.(1976),E23-E28.Publisher: Financ. Officer, Inst. Metall.,London, EnglCODEN: 34VBA9Conference; General Review-written in English.CAN 86:193197AN 1977:193197CAPLUS

 

Abstract

In a review with 23 refs., a creep fracture theory based on cavitational damage in alloys is discussed which takes into account the nonuniaxial variable load and variable temp.

 

Bibliographic Information

On the formation of the diamond grain configuration during high temperature creep and fatigue.Singh, Vakil; Rao, P. Rama; Cocks, G. J.; Taplin, D. M. R..Dep. Metall. Eng.,Banaras Hindu Univ.,Banaras,India.J. Mater. Sci.(1977),12(2),373-83.CODEN: JMTSASJournalwritten in English.CAN 86:144168AN 1977:144168CAPLUS

 

Abstract

Influence of variables on the formation of the diamond grain configuration during high-temp. creep and fatigue deformation of metals was studied. The configuration arose from a balance between grain-boundary sliding, grain-boundary mobility, intragranular deformation, and defect imbalance across the grain boundaries and was stabilized by intergranular cavitation. The phenomenon occurred during high-temp. fatigue in a variety of metals irresp. of their crystal structure. During creep, the behavior was obsd. only in hcp. metals. The occurrence was aided by the limited no. of slip systems which caused high defect imbalances in adjacent grains and high driving forces for grain-boundary migration. The shape of the diamond grain was essentially the same as that of the annealed grain.

 

Bibliographic Information

On the role of temperature fluctuations during microstructural degradation of the cadmium-zinc eutectic. Flanders, N. A.; Taplin, D. M. R.; Kerr, H. W.Steel Co. Canada,Hamilton,Ont.,Can.J. Mater. Sci.(1976),11(11),2051-6.CODEN: JMTSASJournalwritten in English.CAN 86:59126AN 1977:59126CAPLUS

 

Abstract

Fluctuations in the microstructural stability of the Cd-Zn [12681-68-4] eutectic were treated as a model for potential high-temp. turbine-blade alloys. The holding time at the highest cycle temp. had a significant, and previously unrecognized, influence on the rate of microstructural degrdn.The mechanism is discussed.

 

Bibliographic Information

The mechanical behavior of cerium-modified alpha-beta brass at high temperatures.  Chandra, T.; Jonas, J. J.; Taplin, D. M. R..Dep. Metall.,Univ. Wollongong,Wollongong,Aust.J. Mater. Sci.(1976),11(10),1843-8.CODEN: JMTSASJournalwritten in English.CAN 86:7918AN 1977:7918CAPLUS

 

Abstract

The mech. behavior of a fine-grained Cu-38.6% Zn alloy [12621-85-1] with and without 0.07% Ce was studied at 475-675°.Addn. of Ce decreased the flow stress by a factor of 3.This was caused by a decrease in the vol. fraction of the harder a-phase due to the reduced Zn soly.

 

Bibliographic Information

Fracture of a superplastic ternary brass. Sagat, S.; Taplin, D. M. R..Fuel Mater. Div.,Chalk River Nucl. Lab.,Chalk River,Ont.,Can.Acta Metall.(1976),24(4),307-15.CODEN: AMETARJournalwritten in English.CAN 85:181142AN 1976:581142CAPLUS

 

Abstract

Flow and fracture in a strain-rate sensitive brass [60765-61-9] contg. Cu 58.5, Zn 38.5, and Fe 3% were studied at 400-800°.The alloy was superplastic with an optimum ductility at 600°.Plastic flow was accompanied by the continuous development of intergranular and interphase cavities.Failure occurred without measurable external necking.  The instability of plastic flow was analyzed in terms of the development of internal bifurcations and linking of cavities by internal necking.

 

Bibliographic Information

The low-cycle fatigue behavior of OFHC copper and a copper dispersion alloy at elevated temperatures.Cocks, G. J.; Taplin, D. M. R..Dep. Chem. Eng.,Univ. Adelaide,Adelaide,Aust.J. Aust. Inst. Met.(1975),20(4),210-19.CODEN: JAMTAEJournalwritten in English.CAN 85:98068AN 1976:498068CAPLUS

 

Abstract

High-strain, low-cycle fatigue tests carried out at 300-750° on OFHC 99.98% Cu and the com. Cu dispersion alloy, CDA 195 [37333-68-9].Low temps. and high strain amplitudes favored a transgranular failure mode.  However, at 490° and at lower strain amplitudes, failure occurred by the nucleation, growth, and interlinkage of grain boundary cracks.  Under these conditions, the fatigue life of the dispersion alloy based on cycles to failure was higher than that of Cu and was governed by the effects of 2 phases which impeded grain-boundary migration to orientations favorable for grain-boundary sliding during fatigue.  The extent of cracking was greater in Cu and the rate of migration depended on strain amplitude.

 

Bibliographic Information

A note on the relation between cavitation and ductility in microduplex brasses.Chandra, T.; Jonas, J. J.; Taplin, D. M. R..Dep. Metall.,Univ. Woollongong,Wollongong,Aust.J. Aust. Inst. Met.(1975),20(4),220-5.CODEN: JAMTAEJournal written in English.CAN 85:82081AN 1976:482081CAPLUS

 

Abstract

Intergranular and interphase cavitation in binary a-b brasses were investigated at 600° and strain rates 10-5-10-1/sec.Testing was carried out in uniaxial tension under const. true strain-rate conditions.  The a/b ratio varied with Zn concn. from 70/30 to 48/52 vol. %.Both cavitation and fracture processes were dependnent on a/b phase ratio.  According to metallog. the extent of cavitation decreased with increasing b-phase.The high temp. flow stress of binary brass also decreased considerably as the b-phase content in the alloy increased.The cavitation behavior was correlated with the flow stress characteristics of the alloys, and a criterion for failure was suggested.

 

Bibliographic Information

Grain-boundary sliding in alpha iron under monotonic and cyclic loading conditions.Westwood, H. J.; Taplin, D. M. R..W. P. Dobson Res. Lab.,Ontario Hydro,Toronto,Ont.,Can.J. Aust. Inst. Met.(1975),20(3),141-9.CODEN: JAMTAEJournalwritten in English.CAN 85:49953AN 1976:449953CAPLUS

 

 

Abstract

Grain boundary sliding measurements were made on a-Fe tested at elevated temps. under slow tensile, dead-load creep, and low-cycle fatigue conditions.  Under tensile loading, the sliding contribution to the overall strain (the g value) increased with temp. over thh 500-700° range.  At 700°, the amt. of sliding increased with increasing grain size but g decreased.  In creep at 700°, a similar amt. of sliding occurred, but g values were lower.  In low-cycle fatigue at 700°, the sliding rate is an order of magnitude higher than under monotonic conditions.

 

Bibliographic Information

The stability of plastic flow in strain-rate sensitive materials.Sagat, S.; Taplin, D. M. R..Fuel Mater. Div.,Chalk River Nucl. Lab.,Chalk River,Ont.,Can.Met. Sci.(1976),10(3),94-100.CODEN: METSC7Journalwritten in English.CAN 85:24599AN 1976:424599CAPLUS

 

Abstract

A detailed exptl. study of the development of plastic flow was made in a noncavitating superplastic alloy (wrought Pb-Cd eutectic [12618-54-1]).The behavior was analyzed in terms of 2 instabilities, the 1st corresponding to the development of measurable external necks and the 2nd to the rapid growth of 1 neck to cause plastic rupture.

 

Bibliographic Information

The hot fracture of an industrial copper-base alloy.Fleck, R. G.; Beevers, C. J.; Taplin, D. M. R..Ontario Hydro Nucl. Train. Cent.,Ralphton,Ont.,Can.Met. Sci.(1975),9(2),49-54.CODEN: METSC7Journalwritten in English.CAN 84:183683AN 1976:183683CAPLUS

 

Abstract

The hot-fracture characteristics of an industrial Cu-2.8 Al-1.8 Si-0.4 Co [12773-57-8] was studied as a function of grain size (1-720m) at 400-700° by using const.-strain-rate tests (7.0 ´ 10-2 hr). The final fracture mode was dependent on the grain size.  For fine grain sizes an intergranular void sheet mechanism was proposed which was dependent on the strain-rate sensitivity, void size, spacing, and geometry. For coarse grain sizes, the final fracture mode was a result of cracks reaching a crit. length and resulted in continuous crack propagation along the boundaries.  An approach to the prediction of the criterion for fracture by fracture mechanics is discussed for coarse grain-sized alloys.

 

Bibliographic Information

Crane phenomenon in superplastic copper alloys.Taplin, D. M. R.; Chandra, T.Dep. Metall. Mater. Sci.,Univ. Cambridge,Cambridge, Engl.J. Mater. Sci.(1975),10(9),1642-3.CODEN: JMTSASJournalwritten in English.CAN 84:78110AN 1976:78110CAPLUS

 

Abstract

Addn. of 0.07 wt.% Ce [7440-45-1] changed the a/b phase ratio in a Cu-38.6% Zn alloy [58221-20-8].Influence of Ce on strength and ductility was explained in terms of the change in the a/b ratio.

 

Bibliographic Information

Creep fracture of HK 40 petrochemical furnace tube steel.Twigg, R. J.; Taplin, D. M. R..Insp. Dep.,Polym. Corp.,Sarnia,Ont.,Can.Interam. Conf. Mater. Technol., [Proc.], 4th(1975),107-18.Publisher: Cent. Reg. Ayuda Tec.,Mexico City, MexCODEN: 31EAA2Conferencewritten in English.CAN 84:48313AN 1976:48313CAPLUS

 

Abstract

The creep strength of HK40 [12605-30-0] cast stainless steel (C 0.045, Mn 0.70, Si 1.03, Cr 25.4, Ni 21%) was detd. in the heat-treated condition prior to service and after use for 50,000 hr in a petrochem.-furnace tube.Creep-rupture tests were performed in air at 1033 and 1148°K at stresses of 34.5-.apprx.207 N/mm2 on material that had 0-20% room-temp. prestrain. D. measurements were made on specimens after creep testing and related to intergranular-cavity size. An anal. was performed to relate cavity size to a crit. crack size for use in a creep-fracture toughness parameter (Kc).The crack-growth rate (da/dt) is described by the equation da/dt = AKc5.5, in which A is a const.The results indicate that the tubes have a design life of at least 100,000 hr.

 

Bibliographic Information

Investigation of the nucleation of creep cavities by 1 MV electron microscopy. Fleck, R. G.; Taplin, D. M. R.; Beevers, C. J.Chalk River Nucl. Lab.,At. Energy Canada Ltd.,Chalk River,Ont.,Can.Acta Metall.(1975),23(4),415-24.CODEN: AMETARJournalwritten in English.CAN 83:64424AN 1975:464424CAPLUS

 

Abstract

A technique for direct observation during creep was used to study cavities in CDA 638 Cu alloy foils by transmission electron microscopy. Under const. strain rate conditions of .apprx.10-3/hr at 870°K, intergranular cavities were obsd. by optical microscopy to form in the alloy having a grain size 16 m diam. at a tensile strain of .apprx.0.2.Cavity nucleation was assocd. with grain boundary particles. Cavities nucleated on 1 side of the particles and were polyhedral in the early growth stages. Const. load tests on the alloy having a grain size of 530 m showed that nucleation involves a crit. sliding displacement whereby the product of av. grain boundary sliding rate and time is a const. The resulting proportionality const. was (54±5) ´ 10-10m.The surface energy of the alloy as calcd. from the Baluffi-Seigle equation was 1.07 J/m2.

 

Bibliographic Information

Superplastic flow of aluminum bronzes. Bright, M. W. A.; Taplin, D. M. R..Dep. Mech. Eng.,Univ. Waterloo,Waterloo,Ont.,Can.Rheol. Acta(1974),13(4-5),664-9.CODEN: RHEAAKJournalwritten in English.CAN 83:31948AN 1975:431948CAPLUS

 

Abstract

Binary and ternary Al bronzes exhibited max. ductility at temps. corresponding to equivol. proportions of the phases.The temps. decreased with increasing Al content from 8.5 to 10% Al.In ternary alloys contg. <2.0% Fe, considerable grain growth accompanied deformation and max. elongations were .apprx.300%.The optimum strain rate was .apprx.1.2 ´ 10-4/sec.Addn. of 4% Fe insured a fine recrystd. structure and inhibited grain growth when the temp. was raised above that corresponding to equivol. phase proportions.The optimum strain rate was 1.2-1.7 ´ 10-3/sec, and max. elongation was 600-1000%.No ductility anisotropy was obsd. in the binary alloys.Marked anisotropy of superplastic flow was obsd. in ternary alloys contg. 4.0% Fe.Superplasticity was obsd. in Cu-Al alloys having grain size ³30 m.

 

Bibliographic Information

Mechanical behavior of rapidly solidified aluminum/aluminum-copper (Al2Cu) and aluminum/aluminum-nickel (Al3Ni) eutectics at elevated temperatures.Bright, M. W. A.; Taplin, D. M. R.; Kerr, H. W.Dep. Mech. Eng.,Univ. Waterloo,Waterloo,Ont.,Can.J. Eng. Mater. Technol.(1975),97(1),1-9.CODEN: JEMTA8Journalwritten in English.CAN 82:143867AN 1975:143867CAPLUS

 

Abstract

Mech. behavior of directionally solidifed Al-Al2Cu and Al-Al3Ni eutectics was studied in tension at 350-625°.Prepn. of wire was done by continuous drawing from the melt. The microstructure of both eutectics was relatively unstable at elevated temps. even in the absence of deformation, as a result of their fine, imperfect structure in the as-cast conditions. During deformation, spheroidization occurred rapidly so that the fibrous-lamellar reinforcement was largely eliminated. During hot deformation of Al-Al2Cu, the degenerate lamellar structure was gradually replaced by an equiaxed microduplex structure via polygonization of both phases. This structure subsequently demonstrated superplastic flow, with an increase in the strain-rate sensitivity from 0.3 to 0.5.Final failure resulted from nucleation of cavities at Al2Cu-Al2Cu-Al triple junctions with cavity growth along Al2Cu-Al2Cu grain boundaries. The Al-Al3Ni eutectic did not exhibit superplastic flow, probably due to the lower vol. fraction of the Al3Ni which spheroidized during deformation.

 

Bibliographic Information

Techniques of specimen preparation for metallography using a new and unique automated polishing process. Roth, K. H.; Taplin, D. M. R..KENINCO,Toronto,Ont.,Can.Editor(s): McCall, James L.; Mueller, William M.Metallogr. Specimen Prep.:Opt. Electron Microsc., [Proc. Metallogr. Symp.](1974),Meeting Date 1973,129-42.Publisher: Plenum,New York, N. YCODEN: 29UIAFConferencewritten in English.CAN 82:128208AN 1975:128208CAPLUS

 

Abstract

An automatic polishing device is described. Polished materials included Pb-Sn-Sb, Al-Si, Pb-Sb-Sn-As, Inconel X-750, Zn, Cu, Al, C steel, stainless steel, brass, coal, oxide coatings, carbides, and Fe ore pellets. The polishing characteristics were insensitive to compn.

 

Bibliographic Information

Grain size dependence of flow and fracture in a chromium-manganese-nitrogen 300 to 1300.deg.K. Rao, V. Kutumba; Taplin, D. M. R.; Rao, P. Rama.Inst. Technol.,Banaras Hindu Univ.,Varanasi,India.Metall. Trans.(1975),6(1),77-86.CODEN: MTGTBFJournalwritten in English.CAN 82:114728AN 1975:114728CAPLUS

 

Abstract

The influence of 18-184 m polycryst. grain size on the tensile behavior of an austenitic stainless steel was investigated in the temp. range 298-1273°K.Decreasing grain size increases the flow stress at small strains in accordance with the Hall-Petch relation at <873°K.Above 875°K., at low strain rates, the Hall-Petch relation reverses and the flow stress decreases with the grain size.

 

Bibliographic Information

Relation between intergranular cavitation and superplastic flow in an industrial copper base alloy.Fleck, R. G.; Beevers, C. J.; Taplin, D. M. R..Chalk River Nucl. Lab.,At. Energy Canada Ltd.,Chalk River,Ont.,Can.J. Mater. Sci.(1974),9(11),1737-44.CODEN: JMTSASJournalwritten in English.CAN 82:62930AN 1975:62930CAPLUS

 

Abstract

Intergranular cavitation was obsd. during the superplastic deformation of a fine grain (1m) Cu-2.8Al-1.8Si-0.4%Co alloy when tested at ³550°.High-voltage electron microscopy revealed that the cavities were nucleated at twin boundary/grain boundary intersections.  The max. elongation occurs at a higher temp. than that of the max. strain-rate sensitivity.  This behavior is explained in terms of grain-boundary migration which restricts the cavitation.  Texture anal. was used to study the deformation at the temps. of max. elongation and strain-rate sensitivity.  The final fracture mode changes with temp.  At 400°, no cavitation occurs, and fracture involves ductile rupture.  At 500-550°, cavitation occurs, and fracture involves interlinkage of voids by an intergranular void sheet mechanism.  At 800°, grain growth occurs, and fracture occurs by propagation and interlinkage of grain-goundary cracks along grain boundaries.

 

Bibliographic Information

Role of solutes during intergranular failure of zinc under isothermal and thermal cycling creep.  Roth, K. H.; Fleck, R. G.; Taplin, D. M. R..Rubbermaid Ltd.,Toronto,Ont.,Can.Mater. Sci. Eng.(1974),16(3),251-60.CODEN: MSCEAAJournalwritten in English.CAN 82:6764AN 1975:6764CAPLUS

 

Abstract

Isothermal (200°) and thermal cycling (150-250° at 10 cycles/hr) creep and const. strain rate tests were done on Zn, Zn-0.16 Al, and Zn-0.14 at.% Cu.  Thermal cycling increased creep rate and intergranular cavitation.  Intergranular cavitation was limited in Zn but was extensive in the alloys.In Zn-Al, sharp grain boundary cracks formed at boundaries at 90° to the tensile axis.  In Zn-Cu, irregular grain boundary voids were formed on boundaries at 45° to the stress axis.  This behavior is related to the interaction of solute atoms with the vacancy flux during thermal cycling.

 

Bibliographic Information

Creep properties of alpha iron after low-cycle fatigue at 700.deg.Taplin, D. M. R.; Westwood, H. J.Univ. Waterloo,Waterloo,Ont.,Can.Met. Trans.(1974),5(7),1701-4.CODEN: MTGTBFJournalwritten in English.CAN 81:94753AN 1974:494753CAPLUS

 

Abstract

Low-cycle fatigue deformation of a-Fe at 700° results in pronounced grain-boundary migration whereby the boundaries become aligned at 45° to the stress axis.  Since grain-boundary sliding is important in the nucleation and growth of intergranular creep cavities, it was predicted that specimens having an initial 45° grain configuration would have different creep properties from specimens with a random or annealed configuration. For investigation, 2 series of creep tests were made, the 1st onspecimens prefatigued to develop the 45° configuration, and the 2nd on annealed specimens. Prior fatigue deformation to produce the 45° grain configuration resulted in decreased fracture elongation during subsequent creep testing. Specimens with 45° -oriented grain exhibited enhanced grain-boundary sliding, particularly at low creep strains, as compared to annealed specimens. With increasing creep strain the 45° configuration disappeared in the fatigued specimens and the grain configuration approached that of the annealed specimens at high strains.

 

Bibliographic Information

Grain-size strengthening and weakening in a copper base alloy.  Fleck, R. G.; Taplin, D. M. R..Dep. Phys. Metall. Sci. Mater.,Univ. Birmingham,Birmingham,Engl.J. Mater. Sci.(1973),8(7),1052-5.CODEN: JMTSASJournalwritten in English.CAN 80:6368AN 1974:6368CAPLUS

 

Abstract

Grain size strengthening at low temps. and grain size weakening at elevated temps. were studied in Cu-2.8Al-1.8Si-0.4% Co, which exhibits superplasticity.  Room temp. strength increased with decreasing grain size.  An increase in grain size decreased the min. creep rate.  Superplastic deformation occurred at 550° at a strain rate of 3.94 ´ 10-2/min and a 1% flow stress of 24 MN/m2 in 1 m grain sized alloy which exhibited high room temp. strength.

 

Bibliographic Information

Study of intergranular fracture in iron using Auger spectroscopy.Powell, B. D.; Westwood, H. J.; Taplin, D. M. R.; Mykura, M.Dep. Phys.,Univ. Warwick,Coventry,Engl.Met. Trans.(1973),4(10),2357-61.CODEN: MTGTBFJournalwritten in English.CAN 80:6172AN 1974:6172CAPLUS

 

Abstract

Low-temp. impact tests on 3 pure Fe samples showed that the tendency for intergranular fracture is largely independent of prior heat treatment.  The effects of C and O contents and C:O ratio were opposite to those previously reported in that the tendency for intergranular fracture increased with increasing C-O ratio and with decreasing O content.  Examn. of fracture surfaces by Auger spectroscopy showed that S was strongly segregated on the grain boundaries but showed no evidence of O segregation.  The fracture of specimens previously tested in creep or high-temp. fatigue differed from that of untested specimens in that fracture was predominantly transgranular cleavage.

 

Bibliographic Information

Cavitation at grain and phase boundaries during superplastic flow of an aluminum bronze. Dunlop, G. L.; Shapiro, E.; Taplin, D. M. R.; Crane, J.Dep. Metall. Mater. Sci.,Univ. Cambridge,Cambridge,Engl.Met. Trans.(1973),4(9),2039-44.CODEN: MTGTBFJournalwritten in English.CAN 79:117642AN 1973:517642CAPLUS

 

Abstract

Cavity formation was obsd. under certain strain rate conditions during superplastic tensile deformation of Cu-9.5 Al-4% Fe.The cavities form preferentially at a-b interfaces or triple junctions involving both phases. Cavitation is assocd. with grain-boundary sliding, and cavity nucleation probably occurs at points of stress concn. in the sliding interfaces. The ductility is not markedly impaired by the cavities because the high strain-rate sensitivity inhibits the interlinkage of cavities at high strains. A range of strains and strain rates for superplastic forming was detd. for a tolerable vol. fraction of cavities.

 

Bibliographic Information

Role of precipitation parameters upon the creep rupture properties of Inconel alloy X-750.Venkiteswaran, P. K.; Bright, M. W. A.; Taplin, D. M. R..Dep. Mech. Eng.,Univ. Waterloo,Waterloo,Ont.,Can.Mater. Sci. Eng.(1973),11(5),255-68.CODEN: MSCEAAJournalwritten in English.CAN 78:163002AN 1973:163002CAPLUS

 

Abstract

The effect of 9-200 m grain size and pptn. parameters was studied on the creep rupture characteristics of Cr 14.9, Fe 6.98, Ti 2.58, Al 0.61, Nb + Ta 0.92% and balance Ni at 700°.Const. strain rate and const. load creep tests were made on the alloy with ppt. g' particles 0.2-0.4 m diam. and spacing of 0.5-1.0 m.A min. ductility occurred at each grain size.The temp. of this min. increased with increasing grain size. Cavitation leading to intergranular fracture limits rupture life under typical gas turbine conditions. Early in the primary stage, cavities nucleate continuously at triple junctions at the particle-matrix interface and at points along grain boundaries due to particle cracking. Interlinkage to form cracks of a size favoring catastrophic failure is delayed until the tertiary stage. Lowest min. creep rate occurs at intermediate grain sizes, accompanied by a max. rupture life, and is enhanced by a wide ppt.-free zone, discontinuous grain boundary ppts., and a fine distribution of intragranular g' Ni3(Al,Ti).Rupture life is controlled by crack propagation along grain boundaries and negotiation of triple junctions, which depend on ppt.-free zone width and type of grain boundary ppts.Tertiary creep is delayed by a low min. creep rate. Where grain boundary ppt. continuity and ppt.-free zone have opposing effects on creep, the former plays the dominant role in limiting rupture life.

 

Bibliographic Information

Metallographic study of superplasticity and cavitation in microduplex copper-40% zinc. Sagat, S.; Blenkinsop, P.; Taplin, D. M. R..Dep. Mech. Eng.,Univ. Waterloo,Waterloo,Ont.,Can.J. Inst. Metals(1972),100(Sept.),268-74.CODEN: JIMEAPJournalwritten in English.CAN 78:19509AN 1973:19509CAPLUS

 

Abstract

The microstructure and elevated-temp. mech. properties were studied of a/b brass (Cu-40% Zn), produced by extrusion at 500° to give a microduplex structure with a grain (phase) size of 3 m av. diam. A max. neck-free elongation of >525% was obtained at 625° at a strain rate 5.3 ´ 10-4/sec.At this temp. the a/b ratio is 1:1.Grain-boundary sliding and grain growth were obsd. and electron microscopy indicated that the defect structure of the grains remained low during superplastic deformation.Extensive intergranular and interphase cavitation occurred, particularly at high strain rates.

 

Bibliographic Information

Role of grain boundary migration during low-cycle fatigue of a-iron at 450.deg. to 700.deg. Westwood, H. J.; Taplin, D. M. R..Dep. Mech. Eng.,Univ. Waterloo,Waterloo,Ont.,Can.Met. Trans.(1972),3(7),1959-65.CODEN: MTGTBFJournalwritten in English.CAN 77:104494AN 1972:504494CAPLUS

 

Abstract

Low-cycle fatigue tests were made on a-Fe at 450-700°.With increasing temp., the no. of cycles to failure decreased and the fracture changed from mixed transgranular/intergranular to almost entirely intergranular. At 650-700°, there was a marked tendency for grain boundaries to migrate and become aligned preferentially at 45° to the stress axis. The rate of migration was mainly dependent on the strain amplitude. The failure at 700° was caused by nucleation, growth, and linkage of intergranular cavities. Onset of cavitation was delayed until grain boundaries had stabilized at 45° to the stress axis.

 

Bibliographic Information

Superplasticity in a commercial copper dispersion alloy. Fleck, R. G.; Taplin, D. M. R..Dep. Mech. Eng.,Univ. Waterloo,Waterloo,Ont.,Can.Can. Met. Quart.(1972),11(2),299-302.CODEN: CAMQAUJournalwritten in English.CAN 77:65501AN 1972:465501CAPLUS

 

Abstract

The high-temp. ductility of a fine-grained com. Cu dispersion alloy, CDA 638 of compn. Cu-2.8 Al-1.8 Si-0.4% Co, was investigated at 400-800° at strain rates of 10-2-1/min.Ductility was markedly temp.- and strain rate dependent with a max. of 320% at 550° and 3.9 ´ 10-2/min.The strain rate sensitivity of the flow stress was .apprx.0.5 under these conditions and the behaviour can be termed superplastic.Extensive intergranular cavitation was obsd. which restricts the ductility. To optimise ductility in this alloy the factors of both cavitation and strain rate sensitivity must be evaluated.

 

Bibliographic Information

Textures and anisotropic flow of a superplastic aluminum bronze. Dunlop, G. L.; Taplin, D. M. R..Dep. Mech. Eng.,Univ. Waterloo,Waterloo,Ont.,Can.J. Aust. Inst. Metals (1971),16(4),195-203.CODEN: JAMTAEJournalwritten in English.CAN 77:23883AN 1972:423883CAPLUS

 

Abstract

Tensile specimens were cut from a 1-mm-thick cold-rolled sheet of Alloy 619 (Al 9.5, Fe 4, rest Cu) with tensile axes at 0, 45, or 90° to the rolling axis. The specimens were tested in air at 800° using initial strain rates of 0.023, 0.078, and 1.6/min.At low strain rates where the superplastic effect was a max., the max. ductility occurred when the tensile axis was 90° to the rolling axis, and min. ductility occurred at 0°; at a high strain rate, the ductility was not a function of the rolling direction. The anisotropic ductility was explained in terms of a model for superplastic flow involving transition with strain rate of the rate control of grain-boundary slip by accommodation in the matrix. At low strain rates, this process was diffusional while a dislocation glide climb process took over at higher strain rates. The strain ratio, R, of width strain to thickness strain increased with strain until a const. value was reached. The value of R also increased with strain rate and was a function of the angle between the tensile axis and rolling direction.

 

Bibliographic Information

Intergranular fatigue cavitation of alpha-iron at elevated temperatures.Westwood, H. J.; Taplin, D. M. R..Dep. Mech. Eng.,Univ. Waterloo,Waterloo,Ont.,Can.Mater. Sci. Eng.(1972),9(2),118-20.CODEN: MSCEAAJournalwritten in English.CAN 77:8742AN 1972:408742CAPLUS

 

Abstract

A low-cycle fatigue-failure study was made in a-Fe at 450-700° with emphasis on the role of grain-boundary migration during intergranular cavitation. The fatigue life in low-cycle tension compression decreases with increase in temp. from 450 to 700° assocd. with marked grain-boundary cavitation. Failure may be related to grain-boundary sliding and migration to alignment at 45° to the stress axis. At 700°, most migration occurs during the 1st 10 cycles, causing fatigue softening; a stable configuration is not reached until half the life, e.g. 100 cycles. The appearance of cavitation leading to failure coincided with attainment of a stable grain configuration; crack growth appeared strain- rather than time-controlled.

 

Bibliographic Information

Metallographic study of superplasticity in a micrograin aluminum bronze. Dunlop, G. L.; Taplin, D. M. R..Dep. Mech. Eng.,Univ. Waterloo,Waterloo,Ont.,Can.J. Mater. Sci.(1972),7(3),316-24. CODEN: JMTSASJournalwritten in English.CAN 76:157387AN 1972:157387CAPLUS

 

Abstract

The microstructures of micrograin Cu base-Al 0-10-Fe 0-4 alloys, which are superplastic at 800°, were detd. Metallog. studies after deformation at 800° over a range of strain rates encompassing the 3 stage strain-rate hardening behavior common to superplastic materials show that in the low strain-rate range, below that for high values of the strain-rate sensitivity exponent (m), clumps of grains slide together as units with considerable flow in the matrix close to sliding interfaces. After deformation in this low strain-rate range, there is no evidence for dislocation motion within the grains. With increasing strain-rate through and beyond the strain-rate range where peak values of m are recorded, evidence for dislocation motion steadily increases; the tendency for clumps of grains to slide together diminishes; and there is decreased flow in the matrix about the sliding interfaces. The strain rate for max. m shows a strong dependence on the proportion of b-phase in the microstructure and the presence of Fe which refines the grain size. These observations are explained in terms of a flow mechanism whereby the high strain-rate sensitivity range occurs intermediate between a low strain-rate range, where sliding is accommodated by diffusion, and a high strain-rate range, where accommodation is by dislocation movement through the matrix.

 

Bibliographic Information

Tensile characteristics of a superplastic aluminum bronze.Taplin, D. M. R.; Sagat, S.Dep. Mech. Eng.,Univ. Waterloo,Waterloo,Ont.,Can.Mater. Sci. Eng.(1972),9(1),53-5.CODEN: MSCEAAJournalwritten in English.CAN 76:130721AN 1972:130721CAPLUS

 

Abstract

Cu-9.8 Al bronzes are homogenized in the b-phase field and quenched to give a fine shear transformation product which was extruded at 500° to produce a fine micro-duplex (a + g2) structure of 1 mm av. grain/phase diam.; flow strength andelongation were detd. as a function of temp. from 450 to 900° at strain rates of 5 ´ 10-5 to 3 ´ 10-2/sec.Max. elongation of some 700 occurred at 700° in the (a + b) phase field rather than in the (a + g2) phase field; optimum elongation occurred at an a:b ratio of 1:1.The optimum strain rate for max. elongation was 21 ´ 10-4/sec; the redn. in area was .apprx.87.Intergranular and interphase cavities were the cause of mechanistically brittle failure. The mechanism controlling the deformation is believed to be grain-boundary sliding consistent with boundary sliding and strain-rate sensitivity; the mechanism for cavity formation is also assocd. with grain/phase boundary sliding occurring at stress concns. at irregularities in the sliding interfaces.

 

Bibliographic Information

Tensile properties of a superplastic aluminum bronze.Dunlop, G. L.; Taplin, D. M. R..Dep. Metall.,Univ. Cambridge,Cambridge,Engl.J. Mater. Sci.(1972),7(1),84-92.CODEN: JMTSASJournalwritten in English.CAN 76:89297AN 1972:89297CAPLUS

 

Abstract

The high-temp. tensile properties were detd. of a micrograin Cu-9.5 Al-4% Fe alloy, which is superplastic at 800°.Elongations at fracture of >700% are achieved when the nominal strainrate is in the range 3.9 ´ 10-2 to 7.9´ 10-2 min-1.The nature of plastic instability in superplastic materials is considered and it is shown that the amt. of strain at the onset of plastic instability is inversely related to the applied strain rate and is relatively independent of the strain rate sensitivity exponent, m.The onset of plastic instability during a tension test results in an increase of local strain rate at the point of min. cross section and this, together with the existence of a triaxial stress state in the necked region, may produce errors in the m vs. strain rate plot if m is detd. by the change-rate method. The initial strain rate for max. elongation is lower than the strain rate for max. m.This may be ascribed either to the influence of plastic instability or the formation of cavities at the higher strain rates.

 

Bibliographic Information

Anisotropic ductility of a superplastic aluminum bronze. Dunlop, G. L.; Reid, J. D.; Taplin, D. M. R..Dep. Mech. Eng.,Univ. Waterloo,Waterloo,Ont.,Can.Met. Trans.(1971),2(8),2308-10.CODEN: MTGTBFJournalwritten in English.CAN 75:100624AN 1971:500624CAPLUS

 

Abstract

Elongation to fracture and the strain-rate sensitivity exponent, m, were detd. as functions of the angle of the tensile axis to the rolling direction on sheet specimens of alloy CDA 619, with a nominal compn. of Cu-9.5 Al-4% Fe. Engineering strain rates of 2.3 ´ 10-2 min-1, 7.8 ´ 10-2 min-1, and 1.6 min-1 were employed. A marked anisotropic ductility was obsd. at the 2 lower strain rates with max. elongation when the tensile axis was at 90° to the rolling direction. This was not obsd. at the fastest rate. The ductility of the material depends on strain rate, so that the max. ductility occurs at an intermediate rate. In this alloy fracture occurs by the formation and slow interlinkage of cavities which form at the interfaces between phases. The processes of cavity formation, growth, and interlinkage may well control the total elongation achieved in the superplastic flow of this alloy and thus provide an understanding of the anisotropy of elongation.

 

Bibliographic Information

Modification of a Hounsfield tensometer and application to the study of a chromium-manganese-nitrogen stainless steel. Kutumbarao, V. V. P.; Taplin, D. M. R.; Rao, P. Rama.Dep. Metall.,Banaras Hindu Univ.,Varanasi,India.Trans. Indian Inst. Metals(1970),23(3),61-7.CODEN: TIIMA3Journalwritten in English.CAN 74:90146AN 1971:90146CAPLUS

 

Abstract

By using a Hounsfield tensometer modified to perform tension tests at dif ferent temps. (-190 to 1100°) and crosshead speeds (0.25/150 mm-hr-1), an austenitic Ni-free Cr-Mn-N showed the following tensile properties:(i) Between room temp. and -190°, a 10-fold ductility drop occurs with a 3- fold increase in yield strength.(ii) A gradual decrease of strength with a lowering of strain hardening o ccurs between room temp. and 500°.In this temp. range ductility remains high at 40-50% and thedeformatio n is intragranular.(iii) At high temps. (500-1000°) the variation in ductility assocd. with intergranular brittleness shows a min. at 650°.At still higher temps. stress-relieving effects and grain boundary migrati on become prominent and enhance ductility.

 

Bibliographic Information

Influence of polycrystal grain size upon the creep ductility of copper. Fleck, R. G.; Cocks, G. J.; Taplin, D. M. R..Dep. Mech. Eng.,Univ. Waterloo,Waterloo,Ont.,Can.Met. Trans.(1970),1(12),3415-20.CODEN: MTGTBFJournalwritten in English.CAN 74:15389AN 1971:15389CAPLUS

 

Abstract

A study of the relation between grain size and creep ductility was made on O-free high-cond. Cu when the fracture process involves intergranular cavitation. Tests were made at a const. nominal strain-rate of 10-2 hr-1 at 350, 425, and 500°.A peak in the grain size vs. ductility plots was obtained at approx. 30 m for 350°, 60 m for 425°, and 150 m for 500°.The final stage of fracture (cavity linkage) controls ductility, rather than either the rate of nucleation or individual growth of cavities. At coarse grain sizes and low temp. the crack length seems to be crit. and increasing grain size decreases ductility. At fine grain sizes and high temp., failure is by a ductile void-sheet process and the vol. fraction of cavities is controlling so that decreasing grain size decreases ductility.

 

Bibliographic Information

Intergranular cavitation of alpha-brass. Spark, I. J.; Taplin, D. M. R..Dep. Met.,Univ. Melbourne,Parkville,Aust.J. Aust. Inst. Metals(1969),14(4),298-305.CODEN: JAMTAEJournalwritten in English.CAN 72:114398AN 1970:114398CAPLUS

 

Abstract

Intergranular cavitation was induced in cylindrical specimens of a-brass at the temp. of min. ductility, 450°, by const. load creep testing and by slow extension at a const. rate. The change in d. of the specimens indicated that the total cavity vol. was controlled primarily by strain. The elec. resistivity of the specimens reflected variations in the orientation or shape of the cavities with respect to testing time and strain. The primary mode of deformation was grain-boundary sliding. The vol. of each cavity increased primarily by vacancy capture in a stress-induced diffusional process; the vacancy flux was influenced strongly by the area of the cavitated grain boundary and hence by the strain.

 

Bibliographic Information

Creep ductility.Taplin, D. M. R..Dep. Mech. Eng.,Univ. Waterloo,Waterloo,Ont.,Can.Metals Eng. Quart.(1970),10(1),31-4.CODEN: MENQA3Journal; General Reviewwritten in English.CAN 72:103055AN 1970:103055CAPLUS

 

Abstract

A review with 11 refs. is presented in which creep ductility is analyzed and discussed with respect to grain boundary sliding and migration, grain b oundary cavitation, and final fracture.

 

Bibliographic Information

Note on the distribution of cavities during creep.Taplin, D. M. R..Univ. waterloo,Waterloo,Ont.,Can.Phil. Mag.(1969),20(167),1079-82.CODEN: PHMAA4Journalwritten in English.CAN 71:127884AN 1969:527884CAPLUS

 

Abstract

The angular distributions for grain-boundary cavities have been measured on a microsection for Cu 70-Zn 30% a-brass with a range of grain sizes after straining at a const. rate of 10-2 hr.-1 at 450° in an Ar atm. The histograms have been converted to a 3-dimensional least-sqs. distribution curve. Under these conditions of testing a marked effect of grain size is observed. At 55 m av. diam. the cavities are predominantly at 45° to the tensile axis while at 430 m diam. the cavities most frequently occur at 90° to the tensile axis. At fine grain sizes, sliding is more important in the mechanism of cavity growth than at coarse grain sizes.

 

Bibliographic Information

Morphology and growth of creep cavities in a-iron. Wingrove, A. L.; Taplin, D. M. R..Def. Stand. Lab.,Alexandria,Aust.J. Mater. Sci.(1969),4(9),789-96.CODEN: JMTSASJournalwritten in English.CAN 71:127645AN 1969:527645CAPLUS

 

Abstract

Electron fractography has been used to study the intergranular cavities formed in a-iron during slow tensile deformation at high temps. A min. in ductility occurs at .apprx.700°; this coincides with conditions where grain-boundary sliding makes a max. contribution to the overall deformation and where the morphology of the cavities tends to be dendritic and finely terraced. This is explained in terms of the gradient of chem. potential for vacancies which may develop at the cavity periphery during grain-boundary sliding. Under other testing conditions, planar growth is observed and the cavity surface is often faceted.

 

Bibliographic Information

Effect of grain size creep cavitation and ductility in copper. Cocks, G. J.; Taplin, D. M. R..Univ. Waterloo,Waterloo,Ont.,Can.Scr. Met.(1969),3(9),623-6.CODEN: SCRMBUJournalwritten in English.CAN 71:115868AN 1969:515868CAPLUS

 

Abstract

Cu (99.9% pure) tensile specimens were annealed at 435-900° to produce stable grain structures with diams. of 20-110 m.Testing was done at a const. tensile strain-rate of 10-2/hr. in an Ar atm. at 425°.For diams. of 1100-60 m, the effect of decreasing grain-size is to increase the elongation at fracture from .apprx.10 to 65%, while for 60-20 m the elongation drops to <40% at fracture. For all grain sizes, failure was by intergranular cavitation and no difference in the early cavitation behavior was detected between specimens of different grain size. Cavities were able to grow and interlink quite quickly until they consumed a complete grain boundary facet; the crack length was then equal to the distance between triple junctions. Later growth and interlinkage occurred more slowly at a rate controlled by the no. of intersecting triple junctions. The crit. crack length is 500 m.The calcd. work done in creating a new surface is 104 ergs/cm.2For grain diams. >300 m, grain size has little influence upon ductility. Ductility decreases with decreasing grain size <60 m.

 

Bibliographic Information

Relation between flow stress and grain size during creep. Dunlop, G. L.; Taplin, D. M. R..Univ. Waterloo,Waterloo,Ont.,Can.Scr. Met.(1969),3(9),641-3.CODEN: SCRMBUJournalwritten in English.CAN 71:115863AN 1969:515863CAPLUS

 

Abstract

Const. slow strain-rate tests (10-2/hr.) were made on a-brass (Cu 70-Zn 30%) at 450°, conditions at which grain boundary sliding is the dominant mechanism with deformation. The 1% flow stress was measured on specimens with stable av. grain diams. of 28, 55, 90, 230, 430, and 650 m.Flow stress (sF) increases markedly with increasing grain size (d).The overall relation is:sF = s0 + Ad-1/2 + Bf(dn/g) + Cd3, where s0, A, B, and C are all consts. for particular conditions of temp. and strain-rate, and g is the ratio of grain boundary sliding strain to total strain. If the flow stress depends upon the resistance to grain boundary sliding, sF µ d/g.Since g is inversely related to d, sF µ dn, where n is fractionally >1 and may not be a const. with changing grain size.

 

Bibliographic Information

Grain-boundary sliding and cavitation in iron.Wingrove, A. L.; Taplin, D. M. R..Univ. Waterloo,Waterloo,Ont.,Can.Scr. Met.(1969),3(9),649-54.CODEN: SCRMBUJournalwritten in English.CAN 71:115525AN 1969:515525CAPLUS

 

Abstract

Tensile specimens of Fe (contg. several 100 ppm. of O) were electropolished and annealed in a vacuum of 10-5 torr to give a final av. grain intercept length of 180 m.Tests were made in an Ar atm. at const. strain-rates of 5.0 ´ 10-4, 6.6 ´ 10-3, and 5.3 ´ 10-2/hr. The increase in the no. of cavities/cm.3, (Nv), with increasing elongation, is greater the lower the strain-rate. By assuming the relation Nv = Atm (t = time, A and m are const.), nucleation exponents of 0.5, 1.25, and 4 are obtained, in order of increasing strain-rate. The angular distribution of the cavities with respect to the tensile axis also varied considerably with strain-rate. At the slowest rate of deformation, the normal stress across a boundary governs cavity growth with a nucleation exponent of 0.5.At the faster strain-rates, the governing factor is a shear-stress. The fractional decreases in d., with increasing elongation, correlate closely with the rate of cavity nucleation. At the fastest rate of deformation a marked incubation period exists for the onset of cavitation. Although the actual rate of sliding decreases with decreasing strain-rate, this decrease is less than the decrease in strain-rate; i.e., sliding is more important at lower strain-rates. Although sliding contributes more to deformation at the slowest rate of deformation, sliding is more important in the cavitation process at high strain-rates.

 

Bibliographic Information

Metallography of intercrystalline cavities in metals. Taplin, D. M. R.; Barker, L. J.; Cocks, G. J.; Wingrove, A. L.; Gifkins, R. C.Univ. Melbourne,Melbourne,Aust.Radex Rundsch.(1967),(3-4),727-33.CODEN: RAXRAFJournalwritten in German.CAN 68:80907AN 1968:80907CAPLUS

 

Abstract

Cavities which form at grain boundaries during creep present a complex problem for metallography. The theories of nucleation and growth of cavities are examd. in the light of detailed studies of their shape, size, and distribution. The major factors to be assessed are the various methods of prepn. of microspecimens so that cavities are accurately preserved, and the resolution which is available. Several techniques available are reviewed. In optical metallography, the effects of prepn. are examd. particularly using interferometry. In electron metallography, the limiting factor is preservation of the cavities rather than resolution and thin-foil, shadowgraphic and fractographic techniques are discussed and compared. In investigating the kinetics of cavitation, quant. metallography is employed to characterize the shape, vol., surface area, spacing, configuration, and distribution of cavities as a function of strain or time. The problems in all the possible methods are discussed. Some recommendations for the further study of cavities are made.

 

Bibliographic Information

Experiments on the mechanical behavior of polymers and glass.Taplin, D. M. R.; Delatycki, O.Univ. Melbourne,Melbourne,Aust.Met. Mater.(1967),1(1),12-14.CODEN: MEMTA7Journalwritten in English.CAN 68:30836AN 1968:30836CAPLUS

 

Abstract

Various lab. expts. for illustrating the fractural and stress-strain behavior of poly(dimethylsiloxane), natural rubber, poly(methyl methacrylate), and glass are presented.

 

Bibliographic Information

Creep-rupture mechanisms in reactor grade uranium.Taplin, D. M. R.; Cocks, G. J.Univ. Melbourne,Parkville,Aust.J. Nucl. Mater.(1967),23(2),245-8.CODEN: JNUMAMJournalwritten in English.CAN 67:95939AN 1967:495939CAPLUS

 

Abstract

Studies have been made of the mechanisms of creep-rupture in standard "adjusted" U (contg. approx. 500 ppm. Fe, 250 ppm. Al, 600 ppm. C, 300 ppm. O, 20 ppm. N).Const. strain-rate tensile tests were carried out over the temp. range 250-600° in an Ar atm. After straining (both interrupted and to fracture), specimens were quickly cooled to room temp., to prevent post-test annealing, and prepd. for metallography. Final polishing for optical examn. was achieved with a chromic/AcOH/Al2O3 slurry and a Syntron vibratory polisher. In the range 250-400°C. the mechanism of failure is similar to normal ductile rupture. The brittle U(OCN) dendritic and cuboid inclusions fracture transversely to the stress direction at an early stage in the life of a specimen. In the range 400-520°C. intergranular creep-caviation predominates as the mechanism of failure, and ductility remains relatively low. Some inclusions and dendritic cracking were observed, but the main path of failure is intergranular. Grain boundary sliding initiates caviation at grain-corners and grain-edges, and these grow and link by such processes as sliding, tearing, vacancy condensation, and gas collection to cause failure. Around 600° failure is still initiated by cavities formed at grain boundaries, but because of easy stress relaxation at the cavity apices, these do not readily propagate transversely to the stress direction. Thus, large voids elongated in the stress direction are produced due to growth largely by plastic flow. The results differ from those obtained on "pure" wrought U insofar as in the pure material, ductility was higher overall, but also a high ductility was obtained in the range 250-400°, giving a more definite min. in the temp./ductility plot around 400-500°.11 references.

 

Bibliographic Information

Appraisal of certain metallographic techniques for studying cavities.Cocks, G. J.; Taplin, D. M. R..Univ. Melbourne,Melbourne,Aust.Metallurgia(1967),75(451),229-35.CODEN: METLAIJournalwritten in English.CAN 67:76946AN 1967:476946CAPLUS

 

Abstract

The methods available for prepg. microsections for optical metallography were investigated from the viewpoint of the production of a true representation of small cavities at the specimen surface. Certain specialized techniques were used including 2-beam interferometry and taper sectioning. A "rough" diamond finish yields an unsuitable surface for the study of cavities owing to marked collapse, rounding, and filling-in of the cavities. The collapse presumably results from the induced compressive stresses in the surface, the rounding from local abrasion, and the filling-in partly from collection of debris, but it also appears that some local deformation occurs. A "fine" diamond finish is similarly unsatisfactory owing to the same surface damage effects. The surface damage can be reduced by control of the compn. of the diamond paste. With sufficient practice, the MgO skid polish under controlled conditions of chem. attack yields a satisfactory surface finish for the examn. of cavity shapes, profiles, and vols. Light etching can at times be beneficial in removing artifacts without causing undue rounding of cavities. While electropolishing was demonstrated to be unsuitable as a method for prepg. microspecimens which retain cavity profiles accurately, it has some merits. In particular, results so obtained may be less misleading than those from a specimen poorly prepd., esp. if skill in skid-polishing is lacking. For a qual. indication of the existence of cavities, electropolishing is superior to the usual diamond finish. The electron shadowgraphic technique is a useful tool for studying cavities at high magnification, but careful attention to prepn., examn., and interpretation of foils is necessary. The results of the shape and profile of the cavities observed provides further evidence that several mechanisms are responsible for their growth.

 

Bibliographic Information

The tensil eproperties and fracture of uranium between --200° and +900°Taplin, D. M. R..Univ. Melourne,Melbourne,Aust.J. Aust. Inst. Met.(1967),12(1),32-44.CODEN: JAMTAEJournalwritten in English.CAN 67:49397AN 1967:449397CAPLUS

 

Abstract

Tensile strength, reduction of area, and elongation were detd. on reactor grade U in the range of -200 to 900° as related to grain size and strain rate. A max. fracture stress of .apprx.150,000 psi. was found at room temp. and a min. elongation of 25% at 300°.A sharp discontinuous decrease in strength and ductility was observed below room temp. accompanied by a change from ductile to brittle fracture. An increase in grain size and strain rate increased the ductile/brittle transition temp. The b phase was relatively strong and brittle, and the g phase was weak and ductile. Deformation at temp. <450° occurred primarily by twinning.

 

Bibliographic Information

Study of intergranular cavitation in iron by electron microscopy of fracture surfaces.Taplin, D. M. R.; Wingrove, A. L.Univ. Melbourne,Melbourne,Aust.Acta Metall.(1967),15(7),1231-6.CODEN: AMETARJournalwritten in English.CAN 67:46280AN 1967:446280CAPLUS

 

Abstract

This work is part of a study of the nucleation and growth of the cavities which initiate intergranular failure in creep. Pure Fe contg. 0.02% O was chosen.It fractures in a brittle intergranular manner at low temps.After specimens are deformed it is possible to obtain a surface consisting entirely of grain boundaries, thereby enabling even the very early stages of cavitation to be studied by fractography.Dead-load creep and const. (slow) strain-rate tests were made in Ar at various stresses and strain rates at 600, 700 and 850°.After straining (not always to fracture) the samples were rapidly cooled to 25° to prevent post-test annealing effects, then notched and fractured intergranularly under impact at -190°.By careful control, a replica of the complete fracture surface could be obtained.Nine electron micrographs show cavity nucleation at a g-Fe2O3 inclusion in a grain boundary and at a grain-boundary triple junction, growth of grain-corner cavities, and grain-edge cavities.The growth of both grain-edge and grain-corner cavities may be dominated by either diffusional or mech. processes according to the stage of the test and the conditions.

 

Bibliographic Information

Comment on cavity growth mechanisms during creep.Taplin, D. M. R.; Gifkins, R. C.Univ. Melbourne,Melbourne,Aust.Acta Metall.(1967),15(4),650-1.CODEN: AMETARJournalwritten in English.CAN 66:109016AN 1967:109016CAPLUS

 

Abstract

The results of the Davies and Dutton expts. (CA 64, 6247b) provide evidence for the conclusion that vacancy condensation is not an important cause of cavity growth.This comment suggests qualifications which seem to render this conclusion not proven.Both vacancy and sliding mechanisms operate and are important in the enlargement of cavities, although other processes may also contribute, different processes probably being important (dominant) at various stages.Further data are necessary in the different stress situations on such aspects as the shape and size of the cavities, the angles between them and the stress axes, and on the detailed kinetics of cavity growth.This should also include expts. where cavitation is initially less advanced.

 

Bibliographic Information

A study of the mechanism of intergranular creep cavitation by shadowgraphic electron microscopy.Taplin, D. M. R.; Barker, L. J.Univ. Melbourne,Melbourne,Aust.Acta Metall.(1966),14(11),1527-31.CODEN: AMETARJournalwritten in English.CAN 66:13527AN 1967:13527CAPLUS

 

Abstract

The main technique involved electron microscopy of foils prepd. from deformed specimens such that the cavities were revealed

shadowgraphically.a-Brass (Cu 70, Zn 30%) and 99.993% Cu tensile pieces were stamped from 0.024 in. sheet and

annealed 1 hr. at 500° to produce a grain size of »0.001 in. av. diam.Tests were run in air at 400 and 475° 0.05-6 hrs.After

testing, the specimens were H2O-quenched within 1 min. of stress removal.Thin foils were prepd. by electrolytic

polishing.Circles 0.12 in. diam. were masked with a special clamp, and the surplus metal was removed by electrolytic polishing

in 60% H3PO4.No difference between cavities in disks prepd. by the mech. and electrolytic methods was found, and the

simpler punching technique was adopted.The brass was polished in fresh Disapol D.2 for 2 min. at 30 v. below 5°.The Cu was

polished at 40 v. and 10° for 1.5 min.Polishing occurred rapidly with gas evolution at the anode, so that penetration of

electrolyte into the cavities was minimized and an improved preservation of cavity-profile resulted.In thin regions (1000 A.) of

the foil some electrolytic attack of cavities occurred and data were accepted only from areas opaque to 100-kv.

electrons.Shadowgraphs of cavity profiles were obtained from areas .apprx.10,000 A. thick.Ten shadowgraphs are shown for

brass strained 3, 4, 6, and 12% at 400 or 475°.Strain rates were 2 ´ 10-2 and 10-3/hr.

 

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Plymouth, England

February 2002

 

 

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